diff --git a/src/test/java/org/jenkinsci/plugins/workflow/flow/FlowExecutionListTest.java b/src/test/java/org/jenkinsci/plugins/workflow/flow/FlowExecutionListTest.java
index d122897f..6fd65e89 100644
--- a/src/test/java/org/jenkinsci/plugins/workflow/flow/FlowExecutionListTest.java
+++ b/src/test/java/org/jenkinsci/plugins/workflow/flow/FlowExecutionListTest.java
@@ -47,6 +47,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ForkJoinPool;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
 import java.util.logging.LogRecord;
@@ -203,6 +204,8 @@ public class FlowExecutionListTest {
     }
 
     @Test public void stepExecutionIteratorDoesNotLeakBuildsWhenCpsVmIsStuck() throws Throwable {
+        // Make sure ForkJoinPool is not initialized on a thread where its inheritedAccessControlContext would point to a CpsGroovyShell$CleanGroovyClassLoader
+        ForkJoinPool.commonPool().execute(() -> {});
         sessions.then(r -> {
             var notStuck = r.createProject(WorkflowJob.class, "not-stuck");
             notStuck.setDefinition(new CpsFlowDefinition("semaphore 'wait'", true));
@@ -220,10 +223,11 @@ public class FlowExecutionListTest {
             // Let notStuckBuild complete and clean up all references.
             SemaphoreStep.success("wait/1", null);
             r.waitForCompletion(notStuckBuild);
+            notStuck.getLazyBuildMixIn().removeRun(notStuckBuild);
             notStuckBuild = null; // Clear out the local variable in this thread.
             Jenkins.get().getQueue().clearLeftItems(); // Otherwise we'd have to wait 5 minutes for the cache to be cleared.
             // Make sure that the reference can be GC'd.
-            MemoryAssert.assertGC(notStuckBuildRef, true);
+            MemoryAssert.assertGC(notStuckBuildRef, false);
             // Allow stuck #1 to complete so the test can be cleaned up promptly.
             SynchronousBlockingStep.unblock("stuck");
             r.waitForCompletion(stuckBuild);
@@ -231,6 +235,8 @@ public class FlowExecutionListTest {
     }
 
     @Test public void stepExecutionIteratorDoesNotLeakBuildsWhenProgramPromiseIsStuck() throws Throwable {
+        // Make sure ForkJoinPool is not initialized on a thread where its inheritedAccessControlContext would point to a CpsGroovyShell$CleanGroovyClassLoader
+        ForkJoinPool.commonPool().execute(() -> {});
         sessions.then(r -> {
             var stuck = r.createProject(WorkflowJob.class, "stuck");
             stuck.setDefinition(new CpsFlowDefinition(
@@ -254,10 +260,11 @@ public class FlowExecutionListTest {
             // Let notStuckBuild complete and clean up all references.
             SemaphoreStep.success("wait/1", null);
             r.waitForCompletion(notStuckBuild);
+            notStuck.getLazyBuildMixIn().removeRun(notStuckBuild);
             notStuckBuild = null; // Clear out the local variable in this thread.
             Jenkins.get().getQueue().clearLeftItems(); // Otherwise we'd have to wait 5 minutes for the cache to be cleared.
             // Make sure that the reference can be GC'd.
-            MemoryAssert.assertGC(notStuckBuildRef, true);
+            MemoryAssert.assertGC(notStuckBuildRef, false);
             // Allow stuck #1 to complete so the test can be cleaned up promptly.
             r.waitForMessage("Still trying to load StuckPickle for", stuckBuild);
             ExtensionList.lookupSingleton(StuckPickle.Factory.class).resolved = new StuckPickle.Marker();