Material attribute layers issue with texture sample and VT lookups

UE - Rendering Architecture - Materials - Nov 14, 2024

When using material attribute layers in a material layer setup, there is a potential discrepancy in the number of VT Lookups presented in the material instance's Platform Stats. When the same textur ...

[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 ...

Blueprint derived from C++ class not saving correctly

UE - Gameplay - Blueprint - Jul 27, 2015

The blueprint that the user is using loses some data when the editor closes and reopens despite saving all of the content. Note: Currently unsure of what exactly causes this but as I am able to rep ...

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 ...

FBlackboardKeySelector filters aren't applied when recompiling blueprint if a behavior tree asset containing the blueprint added as a service is closed, or if the blueprint is reparented.

UE - AI - BehaviorTree - Sep 24, 2025

Context In Behavior Trees, BT Services can be added to nodes. Those services can have configurable FBlackboardKeySelectors. BlackboardKeys are variables on a blackboard that the behavior tree can r ...

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 ...