Changing MaterialQualityLevel causes a crash due to a ShaderMap mismatch in UniformExpressionCache

UE - Rendering Architecture - Materials - Nov 26, 2025

A crash may occur when changing the MaterialQualitylevel via Scalability due to a race condition. The issue occurs because in ScalabilityCVarsSinkCallback(), when it creates the FGlobalComponentRec ...

Cones for angular constraints not visible is Separate Translucency is disabled

UE - Graphics Features - Apr 14, 2016

A user reported an issue where the cones that represent angular constraints in the PHAT editor are not rendered if Separate Translucency is disabled. This may be related to another issue with Separa ...

Undoing pasting a component will crash ([CrashReport] UE4Editor_CoreUObject!FWeakObjectPtr::IsValid() [weakobjectptr.cpp:48])

UE - Gameplay - Components - Jul 20, 2017

This is a common crash affecting users in 4.16. The callstack is similar to [Link Removed], which was fixed in 4.13. User DescriptionsAccidentally duplicated a blueprint with multiple static mesh ...

[CrashReport] UE4Editor_Kismet!FQuatRotationMatrix::FQuatRotationMatrix() [quatrotationtranslationmatrix.h:43]

UE - Gameplay - Aug 31, 2018

User comment in crash group:Please Contact me to help fix this. I don't know what else to do. 41 FQuatRotationMatrix(const FQuat& Q) 42 ***** : FQuatRotationTranslationMatrix(Q, FVect ...

Skeletal Meshes load unused textures into memory from hard referenced assets. (Skeleton, Physics Assets)

UE - Foundation - Core - UObject - May 1, 2019

Physics Assets & Skeletons referenced by the skeletal mesh will load materials & textures from their default skeletal meshes into the statistics window. Either the statistics window is incorrect abo ...

Does Container Match Tag Query Node doesn't find existing Gameplay Tags in Packaged Project with Nativized Blueprints

UE - Gameplay - Aug 26, 2019

When using the "Does Container Match Tag Query" node doesn't return true when a gameplay container member has the searched for gameplay tag in a blueprint that has been nativized. Packaging in Excl ...

Vehicles with at least one kinematic collision do not function anymore

UE - Simulation - Physics - Oct 30, 2019

Using at least one source of kinematic collision on a vehicle causes animations or movement to not function any longer. This issue persists on child bones and collisions as well. Users are unable to ...

Push based fast array with net.PushModelSkipUndirtiedFastArrays not replicating across multiple PIE sessions

UE - Networking - Sep 19, 2022

The conditions for this bug are fairly specific. The actor must be statically placed, with its only replicated property being the fast array, and net.PushModelSkipUndirtiedFastArrays must be enabled ...

Gameplay Ability System Attribute Modifiers with a duration (including infinite) do not respect tag requirements

UE - Gameplay - Gameplay Ability System - Feb 21, 2024

When using infinite or duration-based effects, required and ignored tags will have no effect on attribute modifiers. This appears to be caused by OnAttributeAggregatorDirty (GameplayEffect.cpp:2917) ...

Safezones on Android not set properly when orientation changes

UE - Platform - Mobile - Nov 5, 2024

Looks like the resize that does the safe zone update is done before the orientation is updated.  I suggested swapping the order to licensee in the UDN ticket and it worked for him.  This should be t ...