diff --git a/pom.xml b/pom.xml
index 48e9111ca..a66d16099 100644
--- a/pom.xml
+++ b/pom.xml
@@ -26,7 +26,7 @@
 
     <groupId>io.getlime.security</groupId>
     <artifactId>powerauth-server-parent</artifactId>
-    <version>1.8.2</version>
+    <version>1.8.3</version>
     <packaging>pom</packaging>
 
     <parent>
diff --git a/powerauth-admin/pom.xml b/powerauth-admin/pom.xml
index 9e8692bc5..4a7bda118 100644
--- a/powerauth-admin/pom.xml
+++ b/powerauth-admin/pom.xml
@@ -11,7 +11,7 @@
     <parent>
         <groupId>io.getlime.security</groupId>
         <artifactId>powerauth-server-parent</artifactId>
-        <version>1.8.2</version>
+        <version>1.8.3</version>
     </parent>
 
     <dependencies>
diff --git a/powerauth-client-model/pom.xml b/powerauth-client-model/pom.xml
index 18b0d35af..1e2df1809 100644
--- a/powerauth-client-model/pom.xml
+++ b/powerauth-client-model/pom.xml
@@ -28,7 +28,7 @@
     <parent>
         <groupId>io.getlime.security</groupId>
         <artifactId>powerauth-server-parent</artifactId>
-        <version>1.8.2</version>
+        <version>1.8.3</version>
     </parent>
 
     <dependencies>
diff --git a/powerauth-fido2-model/pom.xml b/powerauth-fido2-model/pom.xml
index 5420724eb..34c0fa4b3 100644
--- a/powerauth-fido2-model/pom.xml
+++ b/powerauth-fido2-model/pom.xml
@@ -7,7 +7,7 @@
     <parent>
         <groupId>io.getlime.security</groupId>
         <artifactId>powerauth-server-parent</artifactId>
-        <version>1.8.2</version>
+        <version>1.8.3</version>
     </parent>
 
     <artifactId>powerauth-fido2-model</artifactId>
diff --git a/powerauth-fido2/pom.xml b/powerauth-fido2/pom.xml
index 40d6a7247..1dd69b45b 100644
--- a/powerauth-fido2/pom.xml
+++ b/powerauth-fido2/pom.xml
@@ -27,7 +27,7 @@
     <parent>
         <groupId>io.getlime.security</groupId>
         <artifactId>powerauth-server-parent</artifactId>
-        <version>1.8.2</version>
+        <version>1.8.3</version>
     </parent>
 
     <dependencies>
diff --git a/powerauth-java-server/pom.xml b/powerauth-java-server/pom.xml
index 2b04df909..73107a3a0 100644
--- a/powerauth-java-server/pom.xml
+++ b/powerauth-java-server/pom.xml
@@ -29,7 +29,7 @@
     <parent>
         <groupId>io.getlime.security</groupId>
         <artifactId>powerauth-server-parent</artifactId>
-        <version>1.8.2</version>
+        <version>1.8.3</version>
     </parent>
 
     <dependencies>
diff --git a/powerauth-java-server/src/main/java/io/getlime/security/powerauth/app/server/service/behavior/tasks/OperationServiceBehavior.java b/powerauth-java-server/src/main/java/io/getlime/security/powerauth/app/server/service/behavior/tasks/OperationServiceBehavior.java
index 577cbef17..2e9c5083c 100644
--- a/powerauth-java-server/src/main/java/io/getlime/security/powerauth/app/server/service/behavior/tasks/OperationServiceBehavior.java
+++ b/powerauth-java-server/src/main/java/io/getlime/security/powerauth/app/server/service/behavior/tasks/OperationServiceBehavior.java
@@ -374,7 +374,7 @@ public OperationUserActionResponse attemptApproveOperation(OperationApproveReque
             final String expectedUserId = operationEntity.getUserId();
             final boolean activationIdMatches = activationIdMatches(request, operationEntity.getActivationId());
             final boolean operationShouldFail = operationApprovalCustomizer.operationShouldFail(operationEntity, request);
-            if (expectedUserId == null || expectedUserId.equals(userId) // correct user approved the operation
+            if ((expectedUserId == null || expectedUserId.equals(userId)) // correct user approved the operation
                     && operationEntity.getApplications().contains(application.get()) // operation is approved by the expected application
                     && isDataEqual(operationEntity, data) // operation data matched the expected value
                     && factorsAcceptable(operationEntity, factorEnum) // auth factors are acceptable
@@ -419,7 +419,6 @@ && proximityCheckPassed(proximityCheckResult)
                 final Long maxFailureCount = operationEntity.getMaxFailureCount();
 
                 if (failureCount < maxFailureCount) {
-                    operationEntity.setUserId(userId);
                     operationEntity.setFailureCount(failureCount);
                     operationEntity.setAdditionalData(mapMerge(operationEntity.getAdditionalData(), additionalData));
 
@@ -450,7 +449,6 @@ && proximityCheckPassed(proximityCheckResult)
                     response.setOperation(operationDetailResponse);
                     return response;
                 } else {
-                    operationEntity.setUserId(userId);
                     operationEntity.setStatus(OperationStatusDo.FAILED);
                     operationEntity.setTimestampFinalized(currentTimestamp);
                     operationEntity.setFailureCount(maxFailureCount); // just in case, set the failure count to max value
@@ -535,7 +533,7 @@ public OperationUserActionResponse rejectOperation(OperationRejectRequest reques
             }
 
             final String expectedUserId = operationEntity.getUserId();
-            if (expectedUserId == null || expectedUserId.equals(userId) // correct user rejects the operation
+            if ((expectedUserId == null || expectedUserId.equals(userId)) // correct user rejects the operation
                     && operationEntity.getApplications().contains(application.get())) { // operation is rejected by the expected application
 
                 // Reject the operation
diff --git a/powerauth-java-server/src/main/java/io/getlime/security/powerauth/app/server/service/fido2/PowerAuthAssertionProvider.java b/powerauth-java-server/src/main/java/io/getlime/security/powerauth/app/server/service/fido2/PowerAuthAssertionProvider.java
index 17b04ad7d..439c3d6ae 100644
--- a/powerauth-java-server/src/main/java/io/getlime/security/powerauth/app/server/service/fido2/PowerAuthAssertionProvider.java
+++ b/powerauth-java-server/src/main/java/io/getlime/security/powerauth/app/server/service/fido2/PowerAuthAssertionProvider.java
@@ -146,7 +146,10 @@ public AssertionChallenge approveAssertion(String challengeValue, AuthenticatorD
                 @SuppressWarnings("unchecked")
                 final List<String> allowCredentials = (List<String>) operationEntity.getAdditionalData().get(ATTR_ALLOW_CREDENTIALS);
                 final String credentialId = (String) request.getAdditionalData().get(ATTR_CREDENTIAL_ID);
-                return allowCredentials == null || allowCredentials.isEmpty() || allowCredentials.contains(credentialId);
+                final boolean allowCredentialsMatches = allowCredentials == null // no allow credentials at all are expected (null)
+                        || allowCredentials.isEmpty() // no allow credentials at all are expected (empty collection)
+                        || allowCredentials.contains(credentialId); // used credential matches one of expected values
+                return !allowCredentialsMatches;
             });
             final UserActionResult result = approveOperation.getResult();
             final OperationDetailResponse operation = approveOperation.getOperation();
diff --git a/powerauth-java-server/src/test/java/com/wultra/powerauth/fido2/Fido2AuthenticatorTest.java b/powerauth-java-server/src/test/java/com/wultra/powerauth/fido2/Fido2AuthenticatorTest.java
index 54fb71047..1082bdb3a 100644
--- a/powerauth-java-server/src/test/java/com/wultra/powerauth/fido2/Fido2AuthenticatorTest.java
+++ b/powerauth-java-server/src/test/java/com/wultra/powerauth/fido2/Fido2AuthenticatorTest.java
@@ -544,7 +544,7 @@ private void createOperationTemplate() throws Exception {
         templateCreateRequest.setDataTemplate("A2");
         templateCreateRequest.setMaxFailureCount(5L);
         templateCreateRequest.setExpiration(300L);
-        templateCreateRequest.getSignatureType().add(SignatureType.POSSESSION_KNOWLEDGE);
+        templateCreateRequest.getSignatureType().add(SignatureType.POSSESSION);
         operationTemplateService.createOperationTemplate(templateCreateRequest);
     }
 
diff --git a/powerauth-java-server/src/test/java/io/getlime/security/powerauth/app/server/service/behavior/tasks/OperationServiceBehaviorTest.java b/powerauth-java-server/src/test/java/io/getlime/security/powerauth/app/server/service/behavior/tasks/OperationServiceBehaviorTest.java
index 40ed1d602..98425b76d 100644
--- a/powerauth-java-server/src/test/java/io/getlime/security/powerauth/app/server/service/behavior/tasks/OperationServiceBehaviorTest.java
+++ b/powerauth-java-server/src/test/java/io/getlime/security/powerauth/app/server/service/behavior/tasks/OperationServiceBehaviorTest.java
@@ -699,6 +699,108 @@ void testParsingDeviceOperationCancelDetail() throws Exception {
         assertEquals(expectedDevice, detailResponse.getAdditionalData().get("device"));
     }
 
+    @Test
+    void testAnonymousOperationApprovedUserChanged() throws GenericServiceException {
+        final OperationCreateRequest operationCreateRequest = new OperationCreateRequest();
+        operationCreateRequest.setApplications(List.of("PA_Tests"));
+        operationCreateRequest.setTemplateName("test-template");
+        final OperationDetailResponse operation = operationService.createOperation(operationCreateRequest);
+        final OperationApproveRequest approveRequest = new OperationApproveRequest();
+        approveRequest.setOperationId(operation.getId());
+        approveRequest.setUserId("test_user");
+        approveRequest.setData("A2");
+        approveRequest.setApplicationId("PA_Tests");
+        approveRequest.setSignatureType(SignatureType.POSSESSION_KNOWLEDGE);
+        final OperationUserActionResponse response = operationService.attemptApproveOperation(approveRequest);
+        assertEquals(UserActionResult.APPROVED, response.getResult());
+        final OperationDetailRequest detailRequest = new OperationDetailRequest();
+        detailRequest.setOperationId(operation.getId());
+        final OperationDetailResponse operationDetail = operationService.operationDetail(detailRequest);
+        assertEquals("test_user", operationDetail.getUserId());
+    }
+
+    @Test
+    void testAnonymousOperationFailedApproveUserNotChanged() throws GenericServiceException {
+        final OperationCreateRequest operationCreateRequest = new OperationCreateRequest();
+        operationCreateRequest.setApplications(List.of("PA_Tests"));
+        operationCreateRequest.setTemplateName("test-template");
+        final OperationDetailResponse operation = operationService.createOperation(operationCreateRequest);
+        final OperationApproveRequest approveRequest = new OperationApproveRequest();
+        approveRequest.setOperationId(operation.getId());
+        approveRequest.setUserId("invalid_user");
+        approveRequest.setData("invalid_data");
+        approveRequest.setApplicationId("PA_Tests");
+        approveRequest.setSignatureType(SignatureType.POSSESSION_KNOWLEDGE);
+        final OperationUserActionResponse response = operationService.attemptApproveOperation(approveRequest);
+        assertEquals(UserActionResult.APPROVAL_FAILED, response.getResult());
+        final OperationDetailRequest detailRequest = new OperationDetailRequest();
+        detailRequest.setOperationId(operation.getId());
+        final OperationDetailResponse operationDetail = operationService.operationDetail(detailRequest);
+        assertNull(operationDetail.getUserId());
+    }
+
+    @Test
+    void testAnonymousOperationFailedOperationUserNotChanged() throws GenericServiceException {
+        final OperationCreateRequest operationCreateRequest = new OperationCreateRequest();
+        operationCreateRequest.setApplications(List.of("PA_Tests"));
+        operationCreateRequest.setTemplateName("test-template");
+        final OperationDetailResponse operation = operationService.createOperation(operationCreateRequest);
+        for (int i = 0; i < 5; i++) {
+            final OperationApproveRequest approveRequest = new OperationApproveRequest();
+            approveRequest.setOperationId(operation.getId());
+            approveRequest.setUserId("invalid_user");
+            approveRequest.setData("invalid_data");
+            approveRequest.setApplicationId("PA_Tests");
+            approveRequest.setSignatureType(SignatureType.POSSESSION_KNOWLEDGE);
+            final OperationUserActionResponse response = operationService.attemptApproveOperation(approveRequest);
+            if (i == 4) {
+                assertEquals(UserActionResult.OPERATION_FAILED, response.getResult());
+            } else {
+                assertEquals(UserActionResult.APPROVAL_FAILED, response.getResult());
+            }
+        }
+        final OperationDetailRequest detailRequest = new OperationDetailRequest();
+        detailRequest.setOperationId(operation.getId());
+        final OperationDetailResponse operationDetail = operationService.operationDetail(detailRequest);
+        assertNull(operationDetail.getUserId());
+    }
+
+    @Test
+    void testAnonymousOperationRejectUserChanged() throws GenericServiceException {
+        final OperationCreateRequest operationCreateRequest = new OperationCreateRequest();
+        operationCreateRequest.setApplications(List.of("PA_Tests"));
+        operationCreateRequest.setTemplateName("test-template");
+        final OperationDetailResponse operation = operationService.createOperation(operationCreateRequest);
+        final OperationRejectRequest rejectRequest = new OperationRejectRequest();
+        rejectRequest.setOperationId(operation.getId());
+        rejectRequest.setUserId("test_user");
+        rejectRequest.setApplicationId("PA_Tests");
+        final OperationUserActionResponse response = operationService.rejectOperation(rejectRequest);
+        assertEquals(UserActionResult.REJECTED, response.getResult());
+        final OperationDetailRequest detailRequest = new OperationDetailRequest();
+        detailRequest.setOperationId(operation.getId());
+        final OperationDetailResponse operationDetail = operationService.operationDetail(detailRequest);
+        assertEquals("test_user", operationDetail.getUserId());
+    }
+
+    @Test
+    void testAnonymousOperationRejectFailedUserNotChanged() throws GenericServiceException {
+        final OperationCreateRequest operationCreateRequest = new OperationCreateRequest();
+        operationCreateRequest.setApplications(List.of("PA_Tests"));
+        operationCreateRequest.setTemplateName("test-template");
+        final OperationDetailResponse operation = operationService.createOperation(operationCreateRequest);
+        final OperationRejectRequest rejectRequest = new OperationRejectRequest();
+        rejectRequest.setOperationId(operation.getId());
+        rejectRequest.setUserId("test_user");
+        rejectRequest.setApplicationId(APP_ID);
+        final OperationUserActionResponse response = operationService.rejectOperation(rejectRequest);
+        assertEquals(UserActionResult.REJECT_FAILED, response.getResult());
+        final OperationDetailRequest detailRequest = new OperationDetailRequest();
+        detailRequest.setOperationId(operation.getId());
+        final OperationDetailResponse operationDetail = operationService.operationDetail(detailRequest);
+        assertNull(operationDetail.getUserId());
+    }
+
     private void createApplication() throws GenericServiceException {
         boolean appExists = applicationService.getApplicationList().getApplications().stream()
                 .anyMatch(app -> app.getApplicationId().equals(APP_ID));
diff --git a/powerauth-rest-client-spring/pom.xml b/powerauth-rest-client-spring/pom.xml
index 2fe385c1e..fdef654fa 100644
--- a/powerauth-rest-client-spring/pom.xml
+++ b/powerauth-rest-client-spring/pom.xml
@@ -28,7 +28,7 @@
     <parent>
         <groupId>io.getlime.security</groupId>
         <artifactId>powerauth-server-parent</artifactId>
-        <version>1.8.2</version>
+        <version>1.8.3</version>
     </parent>
 
     <dependencies>