Intermittent failure on ValidationEngineTests validateWithParallelCopiedEngine

[dotasek]

Roughly 9/10 executions of this test pass, but on repeated executions, eventually this failure occurs:

org.hl7.fhir.exceptions.FHIRException: Attempt to fetch the profile http://hl7.org/fhir/StructureDefinition/Extension|4.0.1 while generating the snapshot for it
	at org.hl7.fhir.r5.context.BaseWorkerContext.fetchTypeDefinition(BaseWorkerContext.java:2861)
	at org.hl7.fhir.r5.context.ContextUtilities.isDatatype(ContextUtilities.java:315)
	at org.hl7.fhir.r5.renderers.utils.ResourceWrapperNative.determineModelKind(ResourceWrapperNative.java:85)
	at org.hl7.fhir.r5.renderers.utils.ResourceWrapperNative.loadElementChild(ResourceWrapperNative.java:76)
	at org.hl7.fhir.r5.renderers.utils.ResourceWrapperNative.loadTheChildren(ResourceWrapperNative.java:69)
	at org.hl7.fhir.r5.renderers.utils.ResourceWrapper.loadChildren(ResourceWrapper.java:201)
	at org.hl7.fhir.r5.renderers.utils.ResourceWrapper.child(ResourceWrapper.java:260)
	at org.hl7.fhir.r5.renderers.utils.ResourceWrapper.primitiveValue(ResourceWrapper.java:184)
	at org.hl7.fhir.r5.renderers.OperationOutcomeRenderer.buildNarrative(OperationOutcomeRenderer.java:62)
	at org.hl7.fhir.r5.renderers.ResourceRenderer.renderResource(ResourceRenderer.java:105)
	at org.hl7.fhir.validation.ValidatorUtils.messagesToOutcome(ValidatorUtils.java:155)
	at org.hl7.fhir.validation.ValidationEngine.validate(ValidationEngine.java:579)
	at org.hl7.fhir.validation.tests.ValidationEngineTests.lambda$validateWithParallelCopiedEngine$0(ValidationEngineTests.java:88)
	at java.base/java.lang.Thread.run(Thread.java:840)