Unreal Engine Issues
Unreal Engine Issues
check(bRenderStateCreated) fires in SendRenderDynamicData_Concurrent called from FRegisterComponentContext::Process
UE - Rendering - Architecture - RHI - May 18, 2026FRegisterComponentContext::Process() in ActorComponent.cpp iterates over SendRenderDynamicDataPrimitives and calls SendRenderDynamicData_Concurrent() on each. The existing guard checks ::IsValid(Pri ...
Wrong WPO motion vectors due to Periodic World Space node
UE - Rendering - Graphics Features - May 13, 2026We've noticed smearing in grass due to wrong motion vectors. This appears to be caused by lack of previous frame support in the periodic world space node. This is how we fixed it: In MaterialTempl ...
Curve Atlas Row Parameter uses derivative ops when Texture Sample connected to curveTime input
UE - Rendering - Architecture - Materials - May 1, 2026When a Curve Atlas Row Parameter node is used with a Texture Sampler connected to the curve time input, the sample type uses derivative ops. This has negative performance implications for Nanite co ...
When CommonTabListWidgetBase and ScrollBox are arranged vertically, tabs within CommonTabListWidgetBase momentarily become selected when scrolling the ScrollBox upward
UE - Editor - UI Systems - UMG - Mar 19, 2026When attempting to scroll the ScrollBox upward, the cursor briefly shifts focus to another widget (CommonTabListWidgetBase). When logging this behavior using LogSlate VeryVerbose, it can be observed ...
JsonObjectToUStruct removes _ClassName from input FJsonObject, breaking repeated deserialization
UE - Foundation - Mar 18, 2026FJsonObjectConverter::JsonObjectToUStruct removes _ClassName from nested JSON objects during deserialization. Removing Obj->RemoveField(ObjectClassNameKey) from ConvertScalarJsonValueToFPropertyWit ...
Cursor radius set via FSlateApplication::SetCursorRadius is ignored during FHittestGrid hit testing
UE - Editor - UI Systems - Slate - Mar 16, 2026The cursor radius configured through FSlateApplication::SetCursorRadius() is not respected during Slate hit testing. The radius value is correctly stored in FSlateApplication and passed into FHittes ...
UAbilityTask_SpawnActor::BeginSpawningActor may return true when SpawnedActor contains stale value
UE - Foundation - Mar 15, 2026UAbilityTask_SpawnActor::BeginSpawningActor assumes the incoming AActor*& SpawnedActor parameter is nullptr if no actor was spawned, but it does not initialize the parameter at the start of the func ...
NDC Sorting Incorrect
UE - Niagara - Rendering - Mar 12, 2026Using the new NDC BP nodes in 5.7 causes sorting to break; one system, regardless of world placement, is always drawn over the other. Even when the viewpoint puts the dominant system in the foregrou ...
Rare crash when changing scalability settings rapidly
UE - Rendering - Architecture - RHI - Mar 10, 2026It seems like the code in RefreshSamplerStatesCallback() can overlap with FillUniformBuffer when it mutates the Wrap_WorldGroupSettings and Clamp_WorldGroupSettings FSharedSamplerState objects. Addi ...
Panini Lens Projection and Post Process buffers broken
UE - Rendering - Graphics Features - Mar 9, 2026Panini Lens Distortion does not appear to affect some buffers (SceneDepth, CustomDepth, WorldNormal, etc.) consistently. These buffers behaved correctly in 5.3 ...