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

zComponent - Archive - 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 - Runtime - Animation - 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 - Runtime - Character - 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 ...

Projects crash on Android when trying to load mips

UE - Platform - Mobile - Jan 20, 2017

Projects that are deployed in the Debug configuration crash when trying to load mips on the Android device. I do not see this issue when launching a project onto Android using the Test configuratio ...

Child Actor Component outputs error when child class is set to empty using blutility

UE - Gameplay - Blueprint - Nov 30, 2017

Child Actor Component outputs error when child class is set to empty using blutility I attached repro proj. ...

Enabling Skeletal Mesh 'Per Poly Collision' crashes the Editor

UE - Simulation - Physics - Aug 20, 2018

When a Skeletal Mesh isn't assigned, enabling Per Poly Collision on the Skeletal Mesh Component causes the Editor to crash. This issue was reported and tested in 4.20.1 (CL-4233996). This issue was ...

Crash entering PIE without Magic Leap SDK referencing delayhlp.cpp:323

UE - Platform - XR - Jan 31, 2019

Editor crash when PIEing without ML SDK installed on machine. This did not occur at the same CL on a P4 build. This did not occur on a machine with the ML SDK installed. Does not occur in //UE4/Re ...

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 ...

Can't PIE or Save: Editor gets into odd state when editing parameters.

Tools - Jul 20, 2016

I've seen this happen in other areas of the editor as well: Data Table fields (floats) for example. Manually typing in numbers to fields seems less prone to this error; using spinners to drag value ...