Rearranging the position of enumerators in an Enum BP will change references to the enumerators inside Data Tables based on position rather than value

Tools - Nov 12, 2015

Rearranging the position of enumerators in an Enum BP will change references to the enumerators inside Data Tables based on position rather than value. Reproduced in 4.8.3 binary, 4.9.2 binary, 4.1 ...

adjusting the scale of a DM via BPs will not give accurate collision

UE - Simulation - Physics - Destruction - Dec 8, 2014

DESCRIPTION: Adjusting a DMs scale via blueprints will cause issues for the collision of the DM once it has been scaled up or down. Scaling down by half or up by a value of 2 or 3 is easier to see t ...

Sound Track in Matinee Ignoring Track Location and Playing Audio at Beginning of Sound Wave/Cue

Tools - Sep 22, 2015

When scrubbing the Matinee handle with a Sound Track added, no matter the location of the handle, the sound wave associated will play from the beginning of the audio file. Tested in 4.8.3 - 2634408 ...

Using GeoMerge on fragments of a GeometryCollection (GC) will create a new single particle while removing the old particles, but although you end up with less particles, the disk file size of the GC uasset increases.

UE - Simulation - Physics - Destruction - Nov 26, 2024

Using GeoMerge on fragments of a GeometryCollection (GC) will create a new single particle while removing the old particles, but although you end up with less particles, the disk file size of the GC ...

Crash undoing variable change in Animation Blueprint.

OLD - Anim - Aug 1, 2016

Crash occurs when the user changes a variable in the animation blueprint, and then undo's the change. Note that this occurs with any variable being used, but the callstack will be some what differe ...

Sub-world partitions do not properly handle partial editor loading as world partition standalone level instances' spatially loaded actors do not get loaded even when the Level Instance is force loaded or loaded in by region.

UE - World Creation - Worldbuilding Tools - World Partition - Aug 19, 2025

Context Level Instancing is a level-based workflow designed to improve and streamline the level editing experience. In a standalone Level Behavior, when the Level Instance Actor is loaded through it ...

SteamVR turns off vsync globally

UE - Platform - XR - Feb 21, 2020

Additional Info From User: Result: Vsync will get turned off by FSteamVRHMD::Startup() setting a global console variable, regardless of your project configuration. Expected: Vsync is only deacti ...

Swapping between Multiple Cloth Skeletal Meshes and Animation Classes in a Character Blueprint causes the Engine to crash

UE - Simulation - Physics - Aug 2, 2018

When changing Cloth Skeletal Meshes and Animation Blueprints on a Character it will cause the Engine to crash during PIE. This is a regression from 4.19.2 (CL-4033788) as it was working as expected ...

Low-level memory tracking has negative values for "FMallocUnused" and "Untracked"

UE - Foundation - Core - Oct 6, 2020

"FMallocUnused" is immediately bellow 0. "Untracked" is reported to go below 0 after very long playtimes (over 36 hours). Reported in version 4.25.3(CL 13942748). Tested and found negative values f ...

[CrashReport][Assert] UnrealEditor-RHI!FRHIResource::MarkForDelete() [Engine/Source/Runtime/RHI/Private/RHIResources.cpp:49]

UE - Rendering Architecture - Materials - Dec 18, 2024

One of the users described this issue as below. "At seemingly random times while working in the material graph, some action will cause a hitch or freeze, and quickly after the engine will crash, an ...