Unreal Engine Issues
Unreal Engine Issues
Bug - Vertex Interpolator exposing parameters to instance even if its not connected
UE - Rendering - Architecture - Materials - Feb 17, 2026Parameters attached to the input of a Vertex Interpolator Material Expression are visible in the Material Instance, even if the output of the Vertex Interpolator Material Expression is not connected ...
Non-deterministic actor names created by ChildActorComponent if level uses OFPA
UE - Framework - Blueprint - Feb 16, 2026The bug only happens when the ChildActorComponent is added to the BP after placing instances and saving the world. Adding the ChildActorComponent after this will result on the name of the child acto ...
Blackboard decorator node does not abort lower-priority nodes
UE - AI - Feb 16, 2026When a branch of a selector is deactivated, all auxiliary nodes and observer delegates are removed. If the branch is reactivated soon and the CurrentActiveNode remains unchanged, the behavior tree l ...
Compiler Error when including InstancedSkinnedMeshComponent.h
The UE_EXPERIMENTAL macro is not used correctly in InstancedSkinnedMeshComponent.h. It should come after the 'class' keyword & before UInstancedSkinnedMeshComponent as specified in the documentation ...
Material Parameter Collection Track doesn't work in UMG Preview from 5.7
UE - Editor - UI Systems - UMG - Feb 12, 2026The UMG editor allows us to add a Material Parameter Control track to an animation. This track makes it possible to animate parameters used in a material. Designers can scrub the timeline and previe ...
"Move to Level" of Landscape Tool leads component scale mismatch
UE - Graphics Tools - Terrain - Landscape - Feb 12, 2026In UE 5.7.2, when moving a Landscape Component to a sub-level using Landscape Mode > Manage > Move to Level, the proxy transform is not synchronized with the root Landscape when the KeepWorldTransfo ...
HISM causing massive spikes in BuildTreeAsync
UE - Rendering - Architecture - Feb 12, 2026Loading a world partition cell containing dense foliage (30k+ instances per cell) causes spikes on lower end hardware of up to 10-15ms and can observe spikes of 2-5ms on high end hardware too primar ...
Client disconnected due to MissingLevelPackage in editor with Iris and server streaming enabled
UE - World Creation - Worldbuilding Tools - World Partition - Feb 9, 2026When connecting to the server, if the client activates some local cells while the connection is still pending, ULevelStreaming::IsConcernedByNetVisibilityTransactionAck will return false. In this ca ...
Missing logging or error when applying an anim instance to a skeleton that the anim instance doesn't match.
UE - Anim - Runtime - Feb 9, 2026Currently, we detect whether an anim instance is supported by the skeletal mesh and, if it isn't, unreference the instance, but we don't error or warn the user that this happened. This leads to conf ...
[AI] Navmesh tiles are fully removed when a tile containing an automatic navlink is regenerated using Dynamic Modifiers Only generation
UE - AI - Navigation - Feb 9, 2026An unusual interaction has been found when using automatic navlink generation combined with Dynamic Modifiers Only navmesh generation. When an nav area is modified in a tile that contains an automat ...