Unreal Engine Issues
Unreal Engine Issues
Memory leak in FMaterialPSORequestManager
UE - Rendering - 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 - 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 - 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 - 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 - 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 - 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 ...
Skeletal Mesh BLAS updates when not animating
UE - Rendering - RHI - Dec 19, 2025The BLAS for Skeletal Meshes that don't move, or tick get updated every frame even if the animation and skin cache aren't updated. This adds over 1ms to update time. The only exception is if the sk ...
Texture Streaming can randomly streams in all Mips, causing large memory spikes
UE - Rendering - RHI - Dec 5, 2025A possible race condition allows texture instance views to read uninitialized bounds, causing either garbage or zero screen size values to be returned by FRenderAssetInstanceAsyncView::GetRenderAsse ...
Crash on 5.7 when running with the Vulkan RHI and async compute
UE - Rendering - RHI - Dec 4, 2025Making this a placeholder for now. Will fill out the description asap ...
Unreal Engine Fails to Launch with Vulkan SM6 RHI and RenderDoc Auto-Attach Enabled
UE - Rendering - RHI - Dec 3, 2025When launching Unreal Engine with the Vulkan RHI, SM6 and RenderDoc Auto Attach on Startup enabled, the engine fails to initialize with the error: “A compatible Vulkan Driver is required to run the ...