Unreal Engine Issues
Unreal Engine Issues
Water plugin's RVT/ISR shader permutations fail PSO creation with instanced stereo (D3D12 SM6)
UE - Rendering - Architecture - RHI - Jun 4, 2026With Instanced Stereo Rendering enabled and the Water plugin enabled (default), PSO precaching speculatively compiles WorldGridMaterial × FWaterVertexFactory* permutations for the Runtime Virtual Te ...
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 ...
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 ...
Precaching global shaders with r.PSOPrecache.GlobalShaders = 2 crashes on startup
UE - Rendering - Architecture - RHI - Feb 19, 2026A licensee has reported that they are trying to run a cooked project with r.PSOPrecache.GlobalShaders=2 and running into a crash. They believe the problem is in PrecacheComputePipelineStatesForGlob ...
Memory leak in FMaterialPSORequestManager
UE - Rendering - Architecture - RHI - Jan 21, 2026Context: FMaterialPSORequestManager::PrecachePSOs() is called at runtime when an asset utilizing a material is loaded. This occurs during engine init, travel, and when any async or synchronous load ...
HISM flickering when any character is visible
UE - Rendering - Architecture - RHI - Jan 12, 2026On an NVIDIA GPU, Instanced Static Meshes can flicker when a Groom card or mesh LOD is visible. This appears related to an issue rendering the ISM into the Scene Depth. At the end of the Prepass, t ...
Light Function Materials containing a Texture Sample and Rotator nodes will fail RHI Validation
UE - Rendering - Architecture - RHI - Jan 12, 2026Using a Light Function Material that contains a Texture Sample and Rotator nodes will cause RHI Validation to fail with the following error: LogOutputDevice: Error: Ensure condition failed: Bindings ...
FViewElementPDI::DrawLine calls for SDPG_World are not rendered in PIE or in Game
UE - Rendering - Architecture - RHI - Jan 7, 2026When View.Family->EngineShowFlags.CompositeEditorPrimitives is false in the function RenderEditorPrimitivesForDPG. This code picks which version of the batched lines to renderconst FBatchedElements ...
Morph Targets fail to reset to zero
UE - Rendering - Architecture - RHI - Jan 6, 2026"We have encountered a regression in UE 5.7 where Skeletal Mesh Morph Targets do not visually reset when all weights are set to 0.0. The mesh retains the deformation from the previous frame. This i ...
Virtual Memory leak when using specific rendering settings in the template project
UE - Rendering - Architecture - RHI - Dec 20, 2025When a project is run with these settings in a template project, untracked virtual memory increases. Cvars r.GBufferFormat 3 r.Lumen.TraceMeshSDFs 1 r.Lumen.TranslucencyReflections.FrontLayer.Enab ...