Paper2D crashes on flipbooks with dynamic materials

Having flipbooks with dynamic materials and then playing/stopping multiple times crashes the editor.

Download the BP-only repro project.

Quickly alternate between starting PIE and exiting it (press Start PIE and Stop PIE quickly).

The editor should crash after only a few seconds of doing that.

Exception thrown at 0x00000174F26913AA in UnrealEditor.exe: 0xC0000005: Access violation reading location 0x0000000000000050.

FSpriteTextureOverrideRenderProxy::GetMaterialNoFallback(ERHIFeatureLevel::Type InFeatureLevel)
[Inline Frame] FMaterialRenderProxy::UpdateDeferredCachedUniformExpressions::__l14::<lambda_1>::operator()(ERHIFeatureLevel::Type)
[Inline Frame] UMaterialInterface::IterateOverActiveFeatureLevels(FMaterialRenderProxy::UpdateDeferredCachedUniformExpressions::__l14::<lambda_1>)
FMaterialRenderProxy::UpdateDeferredCachedUniformExpressions()
FScene::UpdateAllPrimitiveSceneInfos(FRDGBuilder & GraphBuilder, EUpdateAllPrimitiveSceneInfosAsyncOps AsyncOps)
FSceneInterface::UpdateAllPrimitiveSceneInfos(FRHICommandListImmediate & RHICmdList)
[Inline Frame] FScene::Release::__l2::<lambda_3>::operator()(FRHICommandListImmediate &)
TEnqueueUniqueRenderCommandType<`FScene::Release'::`2'::FReleaseCommandName,`FScene::Release'::`2'::<lambda_3>>::DoTask(ENamedThreads::Type CurrentThread, const TRefCountPtr<FGraphEvent> & MyCompletionGraphEvent)
TGraphTask<TEnqueueUniqueRenderCommandType<`FScene::Release'::`2'::FReleaseCommandName,`FScene::Release'::`2'::<lambda_3>>>::ExecuteTask(TArray<FBaseGraphTask *,TSizedDefaultAllocator<32>> & NewTasks, ENamedThreads::Type CurrentThread, bool bDeleteOnCompletion)
[Inline Frame] FBaseGraphTask::Execute(TArray<FBaseGraphTask *,TSizedDefaultAllocator<32>> & CurrentThread, ENamedThreads::Type)
FNamedTaskThread::ProcessTasksNamedThread(int QueueIndex, bool bAllowStall)
FNamedTaskThread::ProcessTasksUntilQuit(int QueueIndex)
RenderingThreadMain(FEvent * TaskGraphBoundSyncEvent)
FRenderingThread::Run()
FRunnableThreadWin::Run()
FRunnableThreadWin::GuardedRun()