Lightmass Build Hanging at Specific Percentages

UE - Graphics Features - Sep 11, 2015

Lighting will build indefinitely in certain circumstances and can be verified in Swarm Agent that it will continue to process the maps even though the log shows it has completed. This is happening i ...

[StateTree] Linked Asset trees do not properly transition when On Tick transition is triggered on linked asset that transitions to Tree Succeeded

UE - AI - StateTree - Aug 26, 2024

Linked Asset trees do not transition correctly to Tree Succeeded if using an On Tick transition. The Debugger shows that the transition is triggered repeatedly but no state change occurs. Instead, t ...

GAS PlayMontageAndWait: Server applies root motion with wrong scale at last montage tick

UE - Gameplay - Gameplay Ability System - Apr 3, 2024

User reported: when playing an AnimMontage via GameplayAbility with the PlayMontageAndWait ability task that has a custom value for AnimRootMotionTranslationScale, (dedicated) servers can apply an i ...

Morph target is not applied on the first frame in Level Sequence

UE - Anim - Rigging - Dec 4, 2025

When a skeletal mesh with morph targets spawns in the sequence, the morph is not reflected in the first frame.  In the ProcessStage_SkinCache call of SkeletalMesh, MorphVertexBuffer->SectionIds is ...

Generate Particle Event Blueprint node doesnt generate particles at relative "InLocation"

UE - Niagara - Apr 3, 2018

The EventReceiver Spawn module doesnt seem to take in parameters from linked Particle Generated Event. When setting the location of the Blueprint node (In Location), the relative position of the Par ...

For a TMap with C++ enum keys, deleting and re-adding a map entry in the Editor can corrupt the map data.

UE - Editor - Workflow Systems - Jul 19, 2024

When adding an entry to a TMap using UE's property editors, in most cases the new entry comes with a default-initialized key (if such key already exists, the insertion fails). The case of a UENUM de ...

Changing the “show mouse cursor” variable of PlayerController with a mouse button input does not work the same as with a keyboard input

UE - Editor - UI Systems - Slate - Oct 6, 2020

Using the mouse input to show the mouse cursor acts like an Alt+Tab. When clicking the mouse input again to no longer show the cursor, the camera controls stop at the edge of the screen. Reported i ...

Character sliding down a surface can prematurely land before reaching a walkable floor

UE - Gameplay - Player Movement - Apr 3, 2024

Under some circumstances, a character falling and sliding along a sloped surface may get hung up near the bottom of the surface before actually landing on the floor.  This seems to occur when slidin ...

Cannot build project for Shipping when bUseLoggingInShipping is set to true for a project that uses replicated properties

UE - Foundation - Core - Mar 22, 2018

Enabling bUseLoggingInShipping for a project prevents the project from being built for Shipping if the project includes replicated properties. This is only an issue with binary builds of the Engine. ...