RF_WasLoaded is set to False in PIE for instances of a Blueprint if the Blueprint is recompiled

UE - Gameplay - Blueprint - Apr 5, 2019

The RF_WasLoaded flag is set to false for Blueprint instances in PIE if the Blueprint is edited and compiled. This is fixed by saving the level which is a simple workaround but this should be needed ...

Cannot change Collision Profile of BP component instances

UE - Simulation - Physics - Oct 24, 2019

BP instances placed in level cannot have their components' collision profiles modified to anything other than default and custom. Note that this did not occur in 4.22 (after applying the separate ...

Niagara system loses source emitters when moving Engine from 4.22 or earlier to 4.23 or later.

UE - Niagara - Nov 29, 2019

The following code causes this behavior.// NiagaraSystem.cpp for (FNiagaraEmitterHandle& EmitterHandle : EmitterHandles) { EmitterHandle.ConditionalPostLoad(NiagaraVer); if (!EmitterHandl ...

Problems in skeletal mesh merge

UE - Editor - Content Pipeline - Asset Build - May 10, 2021

There are a few issues a licensee has found with the skeletal mesh merge operation. See the UDN for more details and the proposed fixes. Note, the issue with the cloth merge is already logged in a ...

bIgnoreAllPressedKeysUntilRelease only applies to keys in the previous mapping

UE - Gameplay - Input - Jun 16, 2022

This is because the RebuildControlMappings function only checks this flag when you have a mapping that was already added, we should apply this for any new mappings as well.  I'll update the repro s ...

Disabling bLerpUVs in Nanite Settings of Static Mesh causes texture warping in clusters

UE - Graphics Features - Nanite - Jan 21, 2025

The licensee has identified a potential fix by changing if( Settings.bLerpUVs ) to if( Settings.bLerpUVs || UVIndex == 0 ) On line 389 of NaniteBuilder\Private\Cluster.cpp in UE 5.5 ...

Crash while unloading a streaming level while spawned decals exist in the unloaded level

UE - Graphics Features - Aug 18, 2017

When unloading a level containing a decal that is using a dynamic material instance the editor will crash. ...

Editor crash when a Breakpoint is added to a Widget's Tick function

UE - Editor - UI Systems - Aug 18, 2017

Editor crashes when a widget's tick contains a breakpoint at a print string node. Based on 4.16 warning message, this appears to be caused by the text attempting to draw when no draw buffer is avai ...

Editor crash when adding element to Instance array of custom InstanceStaticMeshComponent

UE - Gameplay - Blueprint - Sep 14, 2017

Adding an instance static mesh component to a class causes the editor to crash when an instance is added to a blueprint of the class. Regression: Yes - this behavior does not occur on 4.16.3 (CL 35 ...

Editor Crashes when working in QAGame TM-Sequencer_EventTrack - TCString<TCharType>::Strlen(InName)

UE - Anim - Sequencer - Jul 12, 2017

Editor Crashes when working in QAGame TM-Sequencer_EventTrack - TCString<TCharType>::Strlen(InName) This Assert happens randomly throughout the repro-steps. I am unsure what about the process cause ...