Unreal Engine Issues
Unreal Engine Issues
Instanced Actors: Moving element in editor is not undoable
UE - Engine Scaling - Mass - May 30, 2026Context Instanced Actors can be moved by unchecking Lock Instance Locations on an IAM, and double-clicking into the actor → comp → instance to select an instance. Problem Moving an IA via the giz ...
Instanced Actors: Editor preview don't show correct relative mesh transforms
UE - Engine Scaling - Mass - May 30, 2026Context Actors can be converted into Instanced Actors via the IA plugin. During runtime and in the editor, an instanced actor’s visual is generated from the collection of StaticMeshComponents on th ...
Incorrect CRC hash for shared fragments with FInstancedStruct member
UE - Engine Scaling - Mass - Mar 30, 2026User has encountered an issue with shared fragments that contain a member variable of type FInstancedStruct. It appears that UE::StructUtils::GetStructInstanceCrc32() does not correctly compute the ...
Mass entities initializing fragments on the incorrect archetypes due to shared CreationContext
UE - Engine Scaling - 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 - Engine Scaling - 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 - Engine Scaling - 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 - Engine Scaling - 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 - Engine Scaling - 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 - Engine Scaling - 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 - Engine Scaling - 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. ...