Unreal Engine Issues
Unreal Engine Issues
Crash in FUniformExpressionSet::FillUniformBuffer trying access deleted UTextureCollection
UE - Rendering Architecture - May 30, 2025Crash in FUniformExpressionSet::FillUniformBuffer trying access deleted UTextureCollection (Experimental in 5.6). The licensee describes their crash, their analysis, and a proposed fix: This crash ...
Runing PlayInEditor with NetMode PlayAsClient and a LevelSequence that AutoPlays in the level and is also opened in Sequencer leads to a Fatal world leak crash on 5.5 and up
UE - Anim - Sequencer - May 28, 2025Runing PlayInEditor with NetMode PlayAsClient, a LevelSequence that AutoPlays in the level, contains a Spawnable BP_ThirdPersonCharacter with an animation, and is also opened in Sequencer, leads to ...
Niagara Regression - Looping particle with Spawn Burst Instantaneous on time 0.0 flickers for a frame between loops
UE - Niagara - Jul 16, 2025Note: This worked correctly up to UE 5.4, but repros from UE 5.5 up to mainline latest. If a Niagara Emitter is set up with "Spawn Burst Instantaneous" on time 0.0, and the spawned particle(s) have ...
Saving Behavior Tree with Blueprint task inheriting from native class invalidates Blackboard key when BP contains a function
UE - AI - Jul 8, 2025A regression introduced in UE 5.6 causes Blackboard key selectors in Blueprint tasks to become invalid when the Blueprint inherits from a native subclass of UBTTask_MoveTo (or UBTTask_BlackboardBase ...
Crashes after destroying a skeletal mesh attached via socket name (not bone name), the destroyed mesh remains welded.
UE - Simulation - Physics - Jul 18, 2025On welding physics bodies during primitive component attachment, UPrimitiveComponent::WeldToImplementation() calls GetRootWelded() and then GetBodyInstance() on the returned root. This searches by b ...
Geometry Collection cluster handles leaking and causing ensures with field systems
UE - Simulation - Visual - Aug 26, 2025Geometry Collection cluster handles leaking and causing ensures with field systems. The licensee has shared their analysis: We have been tracking down an assert that seems to happen occasionally wh ...
Copy-pasting an actor property that is a set of strings adds extra quotes and escapes
UE - Editor - Workflow Systems - Aug 24, 2025Copy-pasting an actor property that is a set of strings adds extra quotes and escapes. The licensee has reported: The problem doesn't happen for example for properties of types set of integers, nor ...
BoxOverlapActors fails to catch an Overlaped actor with a particular scale, from a particular position
UE - Simulation - Core - Sep 30, 2025BoxOverlapActors fails to overlap a scaled Floor actor with a particular scale, from a particular position and extent. The setup is really specific and described in Steps to Reproduce. The required ...
Ensure triggered in FBoundsCacheElement::GetValue when adding ISM instances in Construction Script
UE - AI - Oct 8, 2025An ensure is triggered in FBoundsCacheElement::GetValue when adding instances to an InstancedStaticMeshComponent inside a Blueprint’s Construction Script. This occurs when the ISM component is navig ...
Editor will crash when Blueprint Details Panel is dragged across the Event Graph
Tools - May 6, 2015When dragging the Details Panel in a Blueprint across the event graph the editor will crash. [Link Removed] ...