Unreal Engine Issues
Unreal Engine Issues
World Partition - Deleted actors can become unloaded prior to saving
UE - World Creation - Worldbuilding Tools - World Partition - Apr 11, 2025In world partition levels, deleted actors can become unexpectedly unloaded prior to saving, causing loss of work. Specifically, this issue occurs after the undo history has been cleared (either manu ...
Merging Splines causes Engine to Crash in 5.1
UE - World Creation - Worldbuilding Tools - Merge Actor - Dec 15, 2022Attempting to merge two spline actors causes the Engine to crash. This issue occurs with the Steps to Reproduce regardless if there are more branches added to the tree branch spline/enabled, and reg ...
Controller Mapping/Unmapping on some platforms is not ideal for local multiplayer
UE - Gameplay - Input - Nov 19, 2025[Link Removed] The workaround is as I posted in the UDN, to override the viewport client or to make a custom slate input mapping to change this behavior. But, there is a bug with that unmapping/l ...
[AI] WP Dynamic navmesh fails to rebuild tiles with actors that are loaded but not part of the base navmesh.
UE - AI - Navigation - Feb 18, 2025WP dynamic navmesh does not properly react to actors or navigation modifiers that are loaded in areas that the navmesh has not yet streamed into. Although the actors/modifiers are not part of the ba ...
Crash when calling SetState inside state machine OnUpdate
UE - Anim - Sep 5, 2025The crash happens when SetState is called inside the function bound to OutputAnimationPose’s OnUpdate in the animation state. This way of using Set State node is the same as shown in the official do ...
Chaos Trailing Events not exposed to Blueprints and only accessible via Niagara Chaos DI
UE - Simulation - Visual - Apr 22, 2025Chaos Trailing Events not exposed to Blueprints and only accessible via Niagara Chaos DI. The licensee noticed that the Trailing event is not available to BPs. It's expected that the same data avail ...
UNetDriver server-side hitch results in ActorInfo->NextUpdateTime far into future
UE - Networking - Feb 16, 2024A high UWorld::Tick DeltaSeconds (i.e. GameThread hitch) results in a high UNetDriver::TickFlush DeltaSeconds. This DeltaSeconds can high (many seconds) if the hitch is long. This value then affects ...
The Remove-On-Break feature, set on Fracture Mode on Geometry Collections, stops shrinking and shows strange behaviors
UE - Simulation - Visual - Oct 15, 2024The Remove-On-Break (ROB) feature, set on Fracture Mode on Geometry Collections (GC), was supposed to make the particle shrink until it vanishes. When the GC goes to sleep the shrinking stops and sh ...
A GeometryCollection that was broken and is going through shrinking will reset the size of its particles if a second level is broken
UE - Simulation - Visual - Oct 18, 2024Might relate to issue [Link Removed] - "The Remove-On-Break feature, set on Fracture Mode on Geometry Collections, stops shrinking and shows strange behaviors" The added information on this particu ...
Calling BodyInstance.UpdateBodyScale displays erratic behaviors and does not update the rendering scale
UE - Simulation - Core - Nov 22, 2024Calling BodyInstance.UpdateBodyScale displays erratic behaviors and does not update the rendering scale. The licensee has reported and presented a repro project that displays the erratic behavior of ...