Unreal Engine Issues
Unreal Engine Issues
[AI] StateTree Category = Input validation doesn't validate child properties
UE - AI - StateTree - Oct 10, 2025Normally if you have a property in your state tree instance data of the input property(Category = Input), when you compile the state tree, you will get errors if the property does not have a binding ...
HZB Occlusion causes large stalls on the render thread
UE - Rendering - Architecture - RHI - Oct 7, 2025HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...
Incorrect Lumen Scene direct lighting when objects behind masked landscape
UE - Rendering - Graphics Features - Lumen - Oct 5, 2025When objects are placed behind or beneath a masked landscape and r.Lumen.HardwareRayTracing.SurfaceCacheAlphaMasking is enabled, the direct light evaluation is incorrect. There are two workarounds, ...
OculusOpenXRLoader.build.cs should be part of all InstalledBuild
Tech - BuildOps - Infra - Oct 2, 2025The OculusOpenXRLoader module is only required on Android but it should be possible to reference it from any project\plugin that doesn't target that platform. The user that found the problem is ...
Recompiling an ABP that another ABP has a Property Access dependency on without recompiling/linking the other causes a crash
UE - Runtime - Anim BP - Oct 2, 2025The crash comes from the pointers in FAnimSubsystem_PropertyAccess::Library::Indirections in the layer ABP from pointing to old/invalid functions and properties from the trash ABP_Manny, as they hav ...
FNiagaraScalabilityManager incorrectly reactivates a NiagaraComponent that was deactivated by runtime user code
UE - Niagara - Oct 1, 2025Context: The Niagara System is the primary tool to do visual effects inside Unreal. Niagara systems can be culled due to distance. Problem: Once a deactivated Niagara System is culled due to distan ...
Wrong density calculation in UBodySetup::CalculateMass
UE - Runtime - Simulation - Sep 29, 2025Wrong density calculation in UBodySetup::CalculateMass. The licensee has provided the following analysis and suggested fix: In UBodySetup::CalculateMass, the following code is present: // physical ...
[Mobile/Forward Rendering] PlanarReflection does not work when the reflection plane faces certain directions
UE - Platform - Mobile - Sep 24, 2025Note: This repros on 4.27 and all 5.x versions. When using the mobile renderer and/or forward shading, Planar Reflection will simply not work if the reflection plane normal has components that add ...
Post Process Animation Blueprint Crash When Using Blend Node
UE - Runtime - Anim BP - Sep 24, 2025When using a Blend node inside a Post Process Animation Blueprint, the editor crashes while rendering thumbnails. The crash occurs because USkeletonThumbnailRenderer attempts to draw a thumbnail wit ...
TMap "Categories" meta propagates into structs it shouldn't apply to
UE - Gameplay - Gameplay Tags - Sep 22, 2025When using TMap with "Categories" meta UPROPERTY tag for gameplay tags, it propagates into structs that it shouldn't reaching into. The expectation is that it would only impact the layer of gameplay ...