Bug when trying to Ctrl+Z after Replace Actors

UE - Editor - Workflow Systems - Dec 22, 2023

From the UDN case #00649142: My team noticed a bug where sometimes when using "Undo" (Ctrl+Z usually) the BP they are working on disappears in the level. We were able to find a 100% repro case when ...

Attaching skeletons with welding with simulation broken

UE - Simulation - Physics - Nov 4, 2016

Looks like there may be a missed edge cases when welding Skeletal Meshes. If the Weld Parent has Simulate Physics enabled after welding, the parent continuously tries to depenetrate from the child ...

User Struct value set through a component is reset to default when modified through the level instance

UE - Gameplay - Jul 3, 2017

Struct value set through a component is reset to default when modified through the level instance. If it's not set through the component, it works fine. User Description: There is a bug in the eng ...

[CrashReport] UE4Editor_CoreUObject!FLinkerPlaceholderObjectImpl::FindRawPlaceholderContainer() [linkerplaceholderbase.cpp:161]

UE - Gameplay - Blueprint - Sep 27, 2017

This is currently among the top 10 crashes coming out of the 4.17.2 hotfix, affecting a few unique users, and this specific callstack does not appear to have occurred in 4.17.1. This may be a regres ...

Depth reading features on devices without framebuffer fetch are relying on undefined behaviour.

UE - Platform - Mobile - Oct 26, 2016

For devices without framebuffer fetch we are relying on undefined behaviour for depth reading with decals, mod shadows and depth reading materials. (ES2 spec: 3.8.6 Texture Framebuffer Attachment). ...

UBlueprintFileUtilsBPLibrary is inaccessible through Python script

UE - Editor - Workflow Systems - Oct 7, 2020

The BlueprintFileUtilsBPLibrary API is not accessible through python scripts run in the editor. Attempting to run a script utilizing BplueprintFileUtilsBPLibrary results in:LogPython: Error: Traceb ...

Native gameplay tags in plugins are cleared when reading config files

UE - Gameplay - Aug 14, 2024

When references to Gameplay Tags are loaded, it checks to see if they are already registered. If they are not already registered, it will notice it is invalid and may print a warning depending on th ...

Inline retargeting gives different output pose vs retargeting from mesh

UE - Anim - Rigging - Retargeting - Nov 19, 2025

When we perform a retarget from an input pose rather than another mesh, the transforms within the anim bp have already been conformed to the target mesh by translational retargeting and compatible s ...

OnActive Gameplay Cues not activating properly in standalone

UE - Gameplay - Nov 28, 2016

This was reported from https://udn.unrealengine.com/questions/323255/bugfix-onactive-not-triggering-for-gameplaycues-on.html In some case it looks like OnActive gameplay cues are not working proper ...

[CrashReport] FIntroTutorials::AnalyticsEventNameFromTutorial()

Tools - Jul 6, 2017

This is a common crash that appears to have started in the 4.16.1 hotfix, but has occurred with more frequency in 4.16.2. User DescriptionsAfter the blueprint tutorial, I pressed "play", pressed ES ...