diff --git a/importer/markdown/src/test/java/org/itsallcode/openfasttrace/importer/markdown/TestMarkdownImporter.java b/importer/markdown/src/test/java/org/itsallcode/openfasttrace/importer/markdown/TestMarkdownImporter.java
index 8f847892..e47a4e7f 100644
--- a/importer/markdown/src/test/java/org/itsallcode/openfasttrace/importer/markdown/TestMarkdownImporter.java
+++ b/importer/markdown/src/test/java/org/itsallcode/openfasttrace/importer/markdown/TestMarkdownImporter.java
@@ -88,7 +88,8 @@ void testIdentifyTags(final String text)
 
     @ParameterizedTest
     @CsvSource(
-    { "Tags:", "#Needs: abc", "' Needs: abc'", "Needs: änderung" })
+    { "Tags:", "#Needs: abc", "' Needs: abc'", "Needs: änderung", "Tags: -leadingDash", "Tags: trailingDash-",
+            "Tags: tag with spaces", "Tags: Täg" })
     void testIdentifyNonTags(final String text)
     {
         MarkdownAsserts.assertMismatch(MdPattern.TAGS_INT, text);
diff --git a/importer/markdown/src/test/java/org/itsallcode/openfasttrace/importer/markdown/TestMarkdownMarkupImporter.java b/importer/markdown/src/test/java/org/itsallcode/openfasttrace/importer/markdown/TestMarkdownMarkupImporter.java
index 2f6595cc..671435e6 100644
--- a/importer/markdown/src/test/java/org/itsallcode/openfasttrace/importer/markdown/TestMarkdownMarkupImporter.java
+++ b/importer/markdown/src/test/java/org/itsallcode/openfasttrace/importer/markdown/TestMarkdownMarkupImporter.java
@@ -12,7 +12,7 @@
 
 class TestMarkdownMarkupImporter extends AbstractLightWeightMarkupImporterTest
 {
-    private final static ImporterFactory importerFactory = new MarkdownImporterFactory();
+    private static final ImporterFactory importerFactory = new MarkdownImporterFactory();
 
     TestMarkdownMarkupImporter()
     {
diff --git a/testutil/src/main/java/org/itsallcode/openfasttrace/testutil/importer/lightweightmarkup/AbstractLightWeightMarkupImporterTest.java b/testutil/src/main/java/org/itsallcode/openfasttrace/testutil/importer/lightweightmarkup/AbstractLightWeightMarkupImporterTest.java
index b4083f96..53765a5a 100644
--- a/testutil/src/main/java/org/itsallcode/openfasttrace/testutil/importer/lightweightmarkup/AbstractLightWeightMarkupImporterTest.java
+++ b/testutil/src/main/java/org/itsallcode/openfasttrace/testutil/importer/lightweightmarkup/AbstractLightWeightMarkupImporterTest.java
@@ -163,6 +163,7 @@ static Stream<Arguments> tags()
         return Stream.of(
                 Arguments.of("Tags: req , dsn ", List.of("req", "dsn")),
                 Arguments.of("Tags: req ", List.of("req")),
+                Arguments.of("Tags: req_1 ", List.of("req_1")),
                 Arguments.of("Tags: req,dsn ", List.of("req", "dsn")),
                 Arguments.of("Tags: req ,dsn", List.of("req", "dsn")),
                 Arguments.of("Tags: req,dsn", List.of("req", "dsn")),
@@ -171,7 +172,17 @@ static Stream<Arguments> tags()
                 Arguments.of("Tags:\n* req\n* dsn", List.of("req", "dsn")),
                 Arguments.of("Tags:\n * req\n * dsn\n", List.of("req", "dsn")),
                 Arguments.of("Tags:\n* req \n\t* dsn ", List.of("req", "dsn")),
-                Arguments.of("Tags:\n* req\n* dsn", List.of("req", "dsn")));
+                Arguments.of("Tags:\n* req\n* dsn", List.of("req", "dsn")),
+                Arguments.of("Tags:\n* req_1\n* dsn_2", List.of("req_1", "dsn_2")),
+
+                // Inconsistent behavior, see
+                // https://github.com/itsallcode/openfasttrace/issues/423
+                Arguments.of("Tags: _ ", List.of("_")),
+                Arguments.of("Tags: täg1, taeg2", List.of()),
+                Arguments.of("Tags: _tag1, taeg2", List.of("_tag1", "taeg2")),
+                Arguments.of("Tags: -dash, tag", List.of()),
+                Arguments.of("Tags:\n* tag1\n* täg2", List.of("tag1", "täg2")),
+                Arguments.of("Tags:\n* -tag1\n* täg2", List.of("-tag1", "täg2")));
     }
 
     @ParameterizedTest