diff --git a/plugins/scanners/fossid/src/main/kotlin/FossId.kt b/plugins/scanners/fossid/src/main/kotlin/FossId.kt
index 848efc734bc9c..5c3146ea81e37 100644
--- a/plugins/scanners/fossid/src/main/kotlin/FossId.kt
+++ b/plugins/scanners/fossid/src/main/kotlin/FossId.kt
@@ -641,7 +641,7 @@ class FossId internal constructor(
         }.orEmpty()
 
         // Create an issue for each legacy rule.
-        val legacyRules = excludesRules.filterLegacyRules(existingRules, issues)
+        val legacyRules = existingRules.filterLegacyRules(excludesRules, issues)
         if (legacyRules.isNotEmpty()) {
             logger.warn { "${legacyRules.size} legacy rules have been found." }
         }
diff --git a/plugins/scanners/fossid/src/main/kotlin/Utils.kt b/plugins/scanners/fossid/src/main/kotlin/Utils.kt
index 0156df9d54aa5..88cf28acc9a19 100644
--- a/plugins/scanners/fossid/src/main/kotlin/Utils.kt
+++ b/plugins/scanners/fossid/src/main/kotlin/Utils.kt
@@ -84,15 +84,16 @@ private fun PathExclude.mapToRule(): IgnoreRule? {
 }
 
 /**
- * Check if some elements of [rulesToTest] are legacy rules i.e. are not present in a reference list (current object).
- * Create an issue on [issues] for each legacy rule and return a list of the latter.
+ * Filter [IgnoreRule]s which are not contained in the [referenceRules]. These are legacy rules because they were not
+ * created from the [Excludes] defined in the repository configuration. Also create an [Issue] for each legacy rule and
+ * add it to [issues].
  */
 internal fun List<IgnoreRule>.filterLegacyRules(
-    rulesToTest: List<IgnoreRule>,
+    referenceRules: List<IgnoreRule>,
     issues: MutableList<Issue>
 ): List<IgnoreRule> =
-    rulesToTest.filterNot { ruleToTest ->
-        any { it.value == ruleToTest.value && it.type == ruleToTest.type }
+    filterNot { rule ->
+        referenceRules.any { it.value == rule.value && it.type == rule.type }
     }.onEach {
         issues += Issue(
             source = "FossID.compare",
diff --git a/plugins/scanners/fossid/src/test/kotlin/LegacyRulesTest.kt b/plugins/scanners/fossid/src/test/kotlin/LegacyRulesTest.kt
index b086b8405021a..69748b20e071c 100644
--- a/plugins/scanners/fossid/src/test/kotlin/LegacyRulesTest.kt
+++ b/plugins/scanners/fossid/src/test/kotlin/LegacyRulesTest.kt
@@ -43,7 +43,7 @@ class LegacyRulesTest : WordSpec({
             )
             val issues = mutableListOf<Issue>()
 
-            val legacyRules = referenceRules.filterLegacyRules(rulesToTest, issues)
+            val legacyRules = rulesToTest.filterLegacyRules(referenceRules, issues)
 
             issues shouldHaveSize 1
             issues.first() shouldNotBeNull {
@@ -65,7 +65,7 @@ class LegacyRulesTest : WordSpec({
             )
             val issues = mutableListOf<Issue>()
 
-            val legacyRules = referenceRules.filterLegacyRules(rulesToTest, issues)
+            val legacyRules = rulesToTest.filterLegacyRules(referenceRules, issues)
 
             issues should beEmpty()
             legacyRules should beEmpty()