Changing levels after setting an images material to a dynamic material with a widget blueprint that has been added to the viewport within a HUD blueprint will cause a crash

MachineId:E74C21034048BDD873CC6C9A3913CF6C
EpicAccountId:ccbf39de6f9245c0aa23f8e57cc8a566

Unknown exception - code 00000001 (first/second chance not available)

"Fatal error: [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.9\Engine\Source\Editor\UnrealEd\Private\EditorEngine.cpp] [Line: 6229] 
World //Game//FirstPersonB

UE4Editor_Core!FDebug::AssertFailed() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\core\private\misc\outputdevice.cpp:354]
UE4Editor_UnrealEd!UEditorEngine::VerifyLoadMapWorldCleanup() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\editor\unrealed\private\editorengine.cpp:6229]
UE4Editor_Engine!UEngine::LoadMap() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\unrealengine.cpp:9367]
UE4Editor_Engine!UEngine::Browse() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\unrealengine.cpp:8742]
UE4Editor_Engine!UEngine::TickWorldTravel() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\engine\private\unrealengine.cpp:8917]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\editor\unrealed\private\editorengine.cpp:1285]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\editor\unrealed\private\unrealedengine.cpp:366]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\launch\private\launchengineloop.cpp:2428]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.9\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]