There's so many parameters I have a hard time trying to design a minimal test. I'm debugging it atm, and  - I have not a real clue about many things in the stack - it somehow enters the junit vintage engine trying to treat it as a junit 4 test suite or something. I'll keep trying, and sorry if this stacktrace is totally useless to you, but maybe you can read between the lines:
Thread [WorkbenchTestable] (Suspended)	
	DefensiveAllDefaultPossibilitiesBuilder(AllDefaultPossibilitiesBuilder).runnerForClass(Class<?>) line: 36	
	DefensiveAllDefaultPossibilitiesBuilder.runnerForClass(Class<?>) line: 57	
	DefensiveAllDefaultPossibilitiesBuilder(RunnerBuilder).safeRunnerForClass(Class<?>) line: 70	
	ClassSelectorResolver.resolveTestClass(Class<?>, Context) line: 66	
	ClassSelectorResolver.resolve(ClassSelector, SelectorResolver$Context) line: 47	
	EngineDiscoveryRequestResolution.lambda$resolve$2(DiscoverySelector, SelectorResolver) line: 134	
	156049556.apply(Object) line: not available	
	ReferencePipeline$3$1.accept(P_OUT) line: 195	
	ArrayList$ArrayListSpliterator.tryAdvance(Consumer<? super E>) line: 1632	
	ReferencePipeline$Head<E_IN,E_OUT>(ReferencePipeline<P_IN,P_OUT>).forEachWithCancel(Spliterator<P_OUT>, Sink<P_OUT>) line: 127	
	ReferencePipeline$2(AbstractPipeline<E_IN,E_OUT,S>).copyIntoWithCancel(Sink<P_IN>, Spliterator<P_IN>) line: 502	
	ReferencePipeline$2(AbstractPipeline<E_IN,E_OUT,S>).copyInto(Sink<P_IN>, Spliterator<P_IN>) line: 488	
	ReferencePipeline$2(AbstractPipeline<E_IN,E_OUT,S>).wrapAndCopyInto(S, Spliterator<P_IN>) line: 474	
	FindOps$FindOp<T,O>.evaluateSequential(PipelineHelper<T>, Spliterator<S>) line: 150	
	ReferencePipeline$2(AbstractPipeline<E_IN,E_OUT,S>).evaluate(TerminalOp<E_OUT,R>) line: 234	
	ReferencePipeline$2(ReferencePipeline<P_IN,P_OUT>).findFirst() line: 543	
	EngineDiscoveryRequestResolution.resolve(DiscoverySelector, Function<SelectorResolver,Resolution>) line: 185	
	EngineDiscoveryRequestResolution.resolve(DiscoverySelector) line: 125	
	EngineDiscoveryRequestResolution.resolveCompletely(DiscoverySelector) line: 91	
	EngineDiscoveryRequestResolution.run() line: 82	
	EngineDiscoveryRequestResolver<T>.resolve(EngineDiscoveryRequest, T) line: 113	
	VintageDiscoverer.discover(EngineDiscoveryRequest, UniqueId) line: 44	
	VintageTestEngine.discover(EngineDiscoveryRequest, UniqueId) line: 63	
	DefaultLauncher.discoverEngineRoot(TestEngine, LauncherDiscoveryRequest) line: 181	
	DefaultLauncher.discoverRoot(LauncherDiscoveryRequest, String) line: 168	
	DefaultLauncher.discover(LauncherDiscoveryRequest) line: 124	
	TestPlanScannerFilter.accept(Class) line: 56	
	DefaultScanResult.applyFilter(ScannerFilter, ClassLoader) line: 102	
	JUnitPlatformProvider.scanClasspath() line: 143	
	JUnitPlatformProvider.invoke(Object) line: 124	
	NativeMethodAccessorImpl.invoke0(Method, Object, Object[]) line: not available [native method]	
	NativeMethodAccessorImpl.invoke(Object, Object[]) line: 62	
	DelegatingMethodAccessorImpl.invoke(Object, Object[]) line: 43	
	Method.invoke(Object, Object...) line: 566	
	ReflectionUtils.invokeMethodWithArray2(Object, Method, Object...) line: 206	
	ProviderFactory$ProviderProxy.invoke(Object) line: 161	
	ProviderFactory.invokeProvider(Object, ClassLoader, Object, ProviderConfiguration, boolean, StartupConfiguration, boolean) line: 84	
	OsgiSurefireBooter.run(String[]) line: 116	
	UITestApplication(AbstractUITestApplication).runTests() line: 46	
Linux. The choice of a GNU generation.