Actor loses attach component when parent actor goes in and out of relevancy

UE - Networking - Jun 17, 2019

As described in the linked UDN, non-replicated components aren't being hooked up properly after an actor goes out & back into relevancy. The proposed fix sounds correct, calling MoveMapedObjectToUnm ...

USkinnedMeshComponent::PredictedLODLevel can be set below MinLOD

UE - Anim - Rigging - Aug 12, 2019

 Within USkinnedMeshComponent::UpdateLODStatus_Internal, if the USkinnedMeshComponent does not yet have a MeshObject, MaxLODIndex will be left as 0 and as a result PredictedLODLevel will be set to 0 ...

Non-edit layers landscape don't work adequately with Nanite landscape while painting

UE - Graphics Tools - Terrain - Landscape - Oct 24, 2023

Result : while displaying the Nanite version of the landscape, the paint layers behave erratically (see video : [Link Removed])  If rebuilding the Nanite data, the bug gets fixed until the user sta ...

PhysicsControl-enabled controls occasionally teleport to origin

UE - Anim - Apr 22, 2024

Occasionally, PhysicsControl controls will teleport to the world origin. This is sporadic and generally fixes itself either with a restart. In the licensee's case, the controls were also animation d ...

Logic error in TRange::Difference causes crash when you Trim and Preserve Left/Right and unbounded Attach section in the sequencer

UE - Anim - Sequencer - Aug 1, 2024

TRange::Difference function does not handle bounds correctly, causes crash in the sequencer when "Trim And Preserve Left/Right" is used in the user's example project. User provided a potential fix: ...

bIncludeComponentLocationIntoBounds breaks bounds calculations

UE - Anim - Runtime - Aug 13, 2025

Bounds generation when bIncludeComponentLocationIntoBounds is active is broken. Both the calculation of the local bounds and the world bounds are incorrect (see screenshot). When that flag is acti ...

Physics Mover: AI movement and collisions can cause sharp increase in velocity

UE - Gameplay - Player Movement - Mover - Aug 19, 2025

A pawn using the physics mover and using AI movement can sometimes gain an ton of velocity quickly upon colliding with another physics object. It seems to fix it self and revert back to it's origina ...

Crash on stopping PIE after using DemoRec in PIE

UE - Networking - Jan 20, 2016

Crash on stopping PIE after using DemoRec in PIE. Possibly related to [Link Removed] which must be fixed, but happens upon stopping PIE. Reproduced in 4.11.0 Preview 3 binary and Main (//UE4/Dev-Ma ...

Calling functions that have an implicit WorldContextObject parameter in a Blueprint function library will give a compile error about a missing __WorldContext pin

UE - Gameplay - Blueprint - May 21, 2015

Calling functions that have an implicit WorldContextObject parameter (line trace, execute console command, etc) in a Blueprint function library will give a compile error about a missing __WorldConte ...

Axis Scale changes made in Project Settings > Input are ignored in PIE with Dedicated Server enabled

UE - Gameplay - Input - Jun 16, 2015

Axis Scale changes made in Project Settings > Input are ignored in PIE with Dedicated Server enabled. Does not occur while Dedicated Serve is disabled. Reproduced in 4.7.6, 4.8.0, and Main (//depot ...