Unreal Engine Issues

StreamableManager completion callback can happen after being canceled in same frame

FStreamableHandle (used as part of the FStreamableManager system) has a CancelHandle function that stops it from calling any completion callbacks related to that handle (it could cancel the load req ...

USplineComponent::GetSplinePointAt() returns FSplinePoint with incorrect Type

USplineComponent::GetSplinePointAt() returns an FSplinePoint with the ESplinePointType 'CurveCustomTangent' rather than the type from the setup.Expected: It should return the correct type. ...

FlushPressedKeys doesn't clear EventAccumulators, resulting in stale data

From the user:  The root of the problem appears to be that KeyState.EventAccumulator still has events stored in the structure for 'LeftAlt'. So, although UPlayerInput::FlushInput is called when the ...

Map actor reconstruction does not reattach external non-root components

For two map placed actors, if one actor B's non root component is attached to another actor A, the attachment is not retained when actor A reruns its construction script, such as when moving actor A ...

Pre-UE5 serialized FVariant FVector data corruption when deserialized in UE5

FVariant is a struct that implements a union of data types, including FVector. When assigning an FVariant an FVector value in engine versions UE 4.27 or earlier, the FVariant will deserialize incorr ...

The UI layer system in Lyra leaks widgets when changing level

Setting GDelayTrimMemoryDuringMapLoadMode = 2 causes crash on same map reload

GDelayTrimMemoryDuringMapLoadMode is a CVar that controls whether a garbage collection should take place during map change after unloading the previous map and before loading the new one. By default ...

ResavePackagesCommandlet needs to handle resaving ExternalActors for -FixupRedirectors

ResavePackagesCommandlet -fixupredirects fails to fixup pointers from external actors that are pointing to objectredirectors. It fails to fixup those pointers because we specifically skip loading of ...

Delayed movement adjustment can include incorrect movement mode

It's possible for the server to send a client's character a movement correction with the wrong movement mode.  This can occur if a project has client adjustment throttling settings enabled:  Networ ...

In-editor hitch when deleting one actor in a world with many loaded actors

When editing a level with many actors (1000+), deleting an actor results in a noticeable hitch: the editor becomes unresponsive for seconds. This hitch becomes longer the more actors are loaded and ...