diff --git a/java/com/google/gerrit/server/rules/PrologRuleEvaluator.java b/java/com/google/gerrit/server/rules/PrologRuleEvaluator.java
index 8e39b5044c..e61fc90935 100644
--- a/java/com/google/gerrit/server/rules/PrologRuleEvaluator.java
+++ b/java/com/google/gerrit/server/rules/PrologRuleEvaluator.java
@@ -297,7 +297,8 @@ public class PrologRuleEvaluator {
     try {
       return LabelType.checkName(name);
     } catch (IllegalArgumentException e) {
-      return LabelType.checkName("Invalid-Prolog-Rules-Label-Name--" + sanitizeLabelName(name));
+      String newName = "Invalid-Prolog-Rules-Label-Name-" + sanitizeLabelName(name);
+      return LabelType.checkName(newName.replace("--", "-"));
     }
   }
 
diff --git a/javatests/com/google/gerrit/server/rules/PrologRuleEvaluatorTest.java b/javatests/com/google/gerrit/server/rules/PrologRuleEvaluatorTest.java
index f709f5531d..8622b32d35 100644
--- a/javatests/com/google/gerrit/server/rules/PrologRuleEvaluatorTest.java
+++ b/javatests/com/google/gerrit/server/rules/PrologRuleEvaluatorTest.java
@@ -30,18 +30,18 @@ public class PrologRuleEvaluatorTest {
   @Test
   public void labelWithSpacesIsTransformed() {
     assertThat(PrologRuleEvaluator.checkLabelName("Label with spaces"))
-        .isEqualTo("Invalid-Prolog-Rules-Label-Name--Labelwithspaces");
+        .isEqualTo("Invalid-Prolog-Rules-Label-Name-Labelwithspaces");
   }
 
   @Test
   public void labelStartingWithADashIsTransformed() {
     assertThat(PrologRuleEvaluator.checkLabelName("-dashed-label"))
-        .isEqualTo("Invalid-Prolog-Rules-Label-Name---dashed-label");
+        .isEqualTo("Invalid-Prolog-Rules-Label-Name-dashed-label");
   }
 
   @Test
   public void labelWithInvalidCharactersIsTransformed() {
     assertThat(PrologRuleEvaluator.checkLabelName("*urgent*"))
-        .isEqualTo("Invalid-Prolog-Rules-Label-Name--urgent");
+        .isEqualTo("Invalid-Prolog-Rules-Label-Name-urgent");
   }
 }