Crash after 2nd player joins listen server in default game mode

Hi y’all, I encountered a crash when using the default game mode in a world partition level with a single actor - point light (same crashes when you add a static mesh actor). I’ve submitted a bug report using the form already.

Steps to reproduce

  1. Make a new world partition level
  2. In the World Settings tab, set its game mode to the default engine “GameMode”
  3. Click the 3 vertical dots next to the play button
  4. Set number of players to 2
  5. Set Net Mode to “Listen server”
  6. Add a point light actor to the level
  7. Save the level
  8. Play

You’ll get this crash:

 Error: Ensure condition failed: false [File:D:/build/++UE5/Sync/Engine/Source/Runtime/CoreUObject/Private/Misc/PackageName.cpp] [Line: 1273] 
Illegal call to DoesPackageExist: Input '/Memory/UEDPIE_1_WPRT_MainMap_MainGrid_Cell_L0_X0_Y-1_DL0' is not a child of an existing mount point.

Visual Studio output

[2021.08.02-12.57.50:349][366]LogWorld: Bringing World /Game/VyatrJam/Levels/UEDPIE_1_MainMap.MainMap up for play (max tick rate 0) at 2021.08.02-13.57.50
[2021.08.02-12.57.50:349][366]LogWorld: Bringing up level for play took: 0.002295
[2021.08.02-12.57.50:350][366]LogLoad: Took 0.036408 seconds to LoadMap(/Game/VyatrJam/Levels/UEDPIE_0_MainMap)
[2021.08.02-12.57.50:358][367]LogNet: Client netspeed is 100000
[2021.08.02-12.57.50:358][367]LogNet: Join request: /Game/VyatrJam/Levels/MainMenu_TheCrystal?Name=DESKTOP-7QG95N8-5F06405C48BC06C9B9EC79B23DB34EEA?SplitscreenCount=1
[2021.08.02-12.57.50:358][367]LogOnlineSession: Warning: OSS: No game present to join for session (GameSession)
[2021.08.02-12.57.50:359][367]LogNet: Join succeeded: DESKTOP-7QG95N8-5F06
[2021.08.02-12.57.50:398][368]LogOnlineSession: Warning: OSS: No game present to join for session (GameSession)
[2021.08.02-12.57.50:413][369]LogOnlineSession: Warning: OSS: No game present to join for session (GameSession)
[2021.08.02-12.57.50:421][370]LogEngine: Warning: Failed to load /Game/__ExternalActors__/VyatrJam/Levels/MainMap/E9/4V/HKUR8E1408KWB74QD8ADL_UEDPIE_1_WPRT_MainMap_MainGrid_Cell_L0_X0_Y0_DL0
[2021.08.02-12.57.50:421][370]LogLevelStreaming: Warning: UWorldPartitionLevelStreamingDynamic::IssueLoadRequests failed /Memory/UEDPIE_1_WPRT_MainMap_MainGrid_Cell_L0_X0_Y0_DL0
[2021.08.02-12.57.50:484][373]LogPackageName: Error: Illegal call to DoesPackageExist: Input '/Memory/UEDPIE_1_WPRT_MainMap_MainGrid_Cell_L0_X0_Y-1_DL0' is not a child of an existing mount point.
[2021.08.02-12.57.50:484][373]LogOutputDevice: Warning: 

Script Stack (1 frames):
PlayerController.ServerUpdateLevelVisibility

Ensure condition failed: false [File:D:/build/++UE5/Sync/Engine/Source/Runtime/CoreUObject/Private/Misc/PackageName.cpp] [Line: 1273] 
Illegal call to DoesPackageExist: Input '/Memory/UEDPIE_1_WPRT_MainMap_MainGrid_Cell_L0_X0_Y-1_DL0' is not a child of an existing mount point.
[2021.08.02-12.57.50:485][373]LogOutputDevice: Error: Ensure condition failed: false [File:D:/build/++UE5/Sync/Engine/Source/Runtime/CoreUObject/Private/Misc/PackageName.cpp] [Line: 1273] 
Illegal call to DoesPackageExist: Input '/Memory/UEDPIE_1_WPRT_MainMap_MainGrid_Cell_L0_X0_Y-1_DL0' is not a child of an existing mount point.

[2021.08.02-12.57.50:485][373]LogStats:             FDebug::EnsureFailed -  0.001 s
UnrealEditor.exe has triggered a breakpoint.

Call stack

I also encountered this issue, Could you tell me how to solve this crash if you know please?