Unreal Engine Issues
Unreal Engine Issues
Mass entities initializing fragments on the incorrect archetypes due to shared CreationContext
UE - AI - Mass - Feb 3, 2026UMassAgentSubsystem::HandlePendingInitialization creates a single FEntityCreationContext that is reused across all iterations of the PendingAgentEntities loop. When SpawnEntities eventually calls in ...
[AI] Failed check in UMassSpawnerSubsystem::DestroyEntities due to EntityManager still procesing
UE - AI - Mass - Sep 7, 2025It crashed when unspawning an AI which will destroy its entity. Inside DestroyEntities "IsProcessing" is true, but when it breaks into the debugger, "ProcessingScopeCount" is 0 (so IsProcessing shou ...
SharedStructMemory's custom deleter doesn't call ~SharedStructMemory and may result in a memory leak
UE - AI - Mass - Jun 10, 2024FSharedStructMemory uses a custom deleter that calls FMemory::Free, but it doesn't call the destructor. FSharedStructMemory's destructor is responsible for correctly destructing the internal ScriptS ...
Mass Agent Component implementation triggers Aggressive Default Reference Replacement ensure
UE - AI - Mass - Nov 13, 2023Workaround: Construct the DefaultSubobject with ... = CreateDefaultSubobject<UMassAgentComponent>(TEXT("MASS"), true); The issue appears to be that the DefaultSubobject holds a pointer to the CDO ...
City Sample - Parked Cars, Traffic, and Crowds do not spawn while in PIE
UE - AI - Mass - May 1, 2023Repro Rate 10/10 Issue is a Regression as it doesn't occur in 5.1 Parked Cars, Traffic, and Crowds spawn in as expected when launching the project in Game Mode or a Packaged Build Going into the ...
[AI] Destroying an actor while using pooled actors with MassActorSpawnerSubsystem causes a nullptr exception crash
UE - AI - Mass - Mar 19, 2023If an actor that is used in the pooled actor list of UMassActorSpawnerSubsystem is destroyed, it causes a nullptr exception in UMassActorSpawnerSubsystem::SpawnOrRetrieveFromPool. The subsystem atte ...
[AI] FMassBatchedEntityCommand uses wrong scoped access
UE - AI - Mass - Mar 9, 2023FMassBatchedEntityCommand uses UE_MT_SCOPED_READ_ACCESS in both of its Add methods but it writes data to its TArray that it is supposed to be protecting. ...
FMassArchetypeData::ExecutionFunctionForChunk crashes on binding shared fragments
UE - AI - Mass - Feb 14, 2023FMassArchetypeData::ExecutionFunctionForChunk is using wrong mappings while binding shared fragments. It's using RequirementMapping.ChunkFragments while it should use RequirementMapping.ConstSharedF ...
Mass Entity Config not displaying or accepting drag and dropped State Tree assets
UE - AI - Mass - Nov 23, 2022This is not a regression. Tested in //UE5/Release-5.0 CL20979098 Mass Entity Config not displaying or accepting drag and dropped State Tree assets. The only clear way to assign a State Tree is by c ...