diff --git a/platform-tests/src/test/java/org/junit/platform/engine/support/hierarchical/ForkJoinPoolHierarchicalTestExecutorServiceTests.java b/platform-tests/src/test/java/org/junit/platform/engine/support/hierarchical/ForkJoinPoolHierarchicalTestExecutorServiceTests.java
index 2e0648df63b..46c5bcc6caf 100644
--- a/platform-tests/src/test/java/org/junit/platform/engine/support/hierarchical/ForkJoinPoolHierarchicalTestExecutorServiceTests.java
+++ b/platform-tests/src/test/java/org/junit/platform/engine/support/hierarchical/ForkJoinPoolHierarchicalTestExecutorServiceTests.java
@@ -228,7 +228,9 @@ void defersTasksWithIncompatibleLocksOnMultipleLevels() throws Throwable {
 		});
 
 		assertThat(deferredTasks) //
-				.containsExactly(incompatibleTask1, incompatibleTask2, incompatibleTask1); // incompatibleTask1 may be deferred multiple times
+				.startsWith(incompatibleTask1, incompatibleTask2) //
+				.containsOnly(incompatibleTask1, incompatibleTask2) // incompatibleTask1 may be deferred multiple times
+				.containsOnlyOnce(incompatibleTask2);
 		assertThat(taskFactory.tasks) //
 				.hasSize(3 + 3 + 2) //
 				.values().extracting(it -> it.completion.isDone()).containsOnly(true);