There is no particular error. Developer can ignore it.

Steps to Reproduce
  1. Create non-worldpartition level
  2. Add sublevel (steaming method : Blueprint)
  3. Create a blueprint 
  4. Put nodes so that LoadStreamingLevel and UnloadStreamingLevel are executed on the same tick [Link Removed]
  5. Start PIE and execute the nodes



Ensure occurs :

Ensure condition failed: false [File:D:\dev\UnrealEngine-5.2.0\Engine\Source\Runtime\Engine\Private\LevelStreaming.cpp] [Line: 1018] 

     UnrealEditor-Engine-Win64-Debug.dll!ULevelStreaming::UpdateStreamingState(bool & bOutUpdateAgain, bool & bOutRedetermineTarget) Line 1018    C++
     UnrealEditor-Engine-Win64-Debug.dll!UWorld::UpdateLevelStreaming() Line 3897    C++
     UnrealEditor-Engine-Win64-Debug.dll!UGameViewportClient::Draw(FViewport * InViewport, FCanvas * SceneCanvas) Line 1597    C++
     UnrealEditor-Engine-Win64-Debug.dll!FViewport::Draw(bool bShouldPresent) Line 1852    C++
     UnrealEditor-UnrealEd-Win64-Debug.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 2162    C++
     UnrealEditor-UnrealEd-Win64-Debug.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 519    C++
     UnrealEditor-Win64-Debug.exe!FEngineLoop::Tick() Line 5812    C++
     UnrealEditor-Win64-Debug.exe!EngineTick() Line 62    C++
     UnrealEditor-Win64-Debug.exe!GuardedMain(const wchar_t * CmdLine) Line 191    C++
     UnrealEditor-Win64-Debug.exe!LaunchWindowsStartup(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow, const wchar_t * CmdLine) Line 233    C++
     UnrealEditor-Win64-Debug.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * pCmdLine, int nCmdShow) Line 284    C++
     [Inline Frame] UnrealEditor-Win64-Debug.exe!invoke_main() Line 102    C++
     UnrealEditor-Win64-Debug.exe!__scrt_common_main_seh() Line 288    C++
     kernel32.dll!00007ff8b5217614()    Unknown
     ntdll.dll!00007ff8b6d026a1()    Unknown

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ComponentUE - World Creation - Worldbuilding Tools
Affects Versions5.2
Target Fix5.3
Fix Commit25789387
Main Commit25789387
CreatedMay 29, 2023
ResolvedJun 5, 2023
UpdatedJun 12, 2023