I have this exact issue with my project with this callstack whenever I try to launch the editor:
Assertion failed: !Object->HasAnyFlags(RF_NeedLoad | RF_NeedInitialization) [File:D:\build\++UE5\Sync\Engine\Source\Runtime\CoreUObject\Private\Serialization\AsyncLoading2.cpp] [Line: 10517]
Object='BP_CombatSystem_C /Game/Blueprints/Core/BP_CombatSystem.Default__BP_CombatSystem_C' (000002036293B900), Flags=Public | ClassDefaultObject | ArchetypeObject | NeedLoad | WasLoaded, InternalFlags=0x04508000
UnrealEditor_Core
UnrealEditor_CoreUObject
I was able to fix it once by reverting the BP to an earlier version, but after remaking the changes it started to happen again. I didn’t even have any errors or anything in them. I’ll try deleting the file and recreating it entirely, but any help on how to fix this issue will be great.