I have the same callstack on a crash in our loading screen. I am simply making an image widget cycle between 4 textures.
> RiverGame-XboxOne-Debug.exe!`FSlateRHIResourceManager::FindOrCreateDynamicTextureResource'::`36'::EURCMacro_UpdateSlateUTextureResource::DoTask(ENamedThreads::Type CurrentThread, const TRefCountPtr<FGraphEvent> & MyCompletionGraphEvent) Line 633 C++
RiverGame-XboxOne-Debug.exe!TGraphTask<`FSlateRHIResourceManager::FindOrCreateDynamicTextureResource'::`36'::EURCMacro_UpdateSlateUTextureResource>::ExecuteTask(TArray<FBaseGraphTask *,FDefaultAllocator> & NewTasks, ENamedThreads::Type CurrentThread) Line 798 C++
RiverGame-XboxOne-Debug.exe!FBaseGraphTask::Execute(TArray<FBaseGraphTask *,FDefaultAllocator> & NewTasks, ENamedThreads::Type CurrentThread) Line 329 C++
RiverGame-XboxOne-Debug.exe!FTaskThread::ProcessTasks(int QueueIndex, bool bAllowStall) Line 539 C++
RiverGame-XboxOne-Debug.exe!FTaskThread::ProcessTasksUntilQuit(int QueueIndex) Line 340 C++
RiverGame-XboxOne-Debug.exe!FTaskGraphImplementation::ProcessThreadUntilRequestReturn(ENamedThreads::Type CurrentThread) Line 1094 C++
RiverGame-XboxOne-Debug.exe!RenderingThreadMain(FEvent * TaskGraphBoundSyncEvent) Line 311 C++
RiverGame-XboxOne-Debug.exe!FRenderingThread::Run() Line 430 C++
RiverGame-XboxOne-Debug.exe!FRunnableThreadWin::Run() Line 221 C++
RiverGame-XboxOne-Debug.exe!FRunnableThreadWin::GuardedRun() Line 193 C++
RiverGame-XboxOne-Debug.exe!FRunnableThreadWin::_ThreadProc(void * pThis) Line 67 C++