Unreal Engine Issues
Unreal Engine Issues
Texture streaming uses ISM component bounds instead of closest ISM instance
UE - Rendering - Architecture - Jan 22, 2026When regular texture streaming is used (not virtual textures), the largest mips are always loaded for ISM mesh textures whenever the camera is inside the bounds of the ISM even if the instances are ...
StaticMesh export to FBX crashes if UVElements has more channels than VertexInstanceUVs
UE - Editor - Content Pipeline - FBX - Jan 22, 2026As indicated in the repro steps, we have a StaticMesh asset that, for some reason, has a mismatch in their serialized bulk data where:MeshDescription->GetNumUVElementChannels() == 2FStaticMeshConstA ...
Custom Primitive Data is not affected in the skeletal mesh on BP instances in the editor
UE - Rendering - Architecture - Jan 22, 2026Editing Custom Primitive Data values in the details panel of a placed BP actor with a Skeletal Mesh component does not reflect in the Editor viewport. ...
PCGs Duplicate Point node option to apply in Relative Space has metadata warnings and crashes editor.
UE - World Creation - Procedural Tools - Jan 21, 2026When using the PCG Duplicate Point node's "Direction Applied in Relative Space" option, this deletes or messes with the output metadata and, if connected to an output or using it's debug mode, will ...
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 ...
UEditorEngine::OnAllPIEInstancesStarted() called prematurely, multiple times, while PIE clients are starting
UE - Gameplay - Jan 21, 2026Context UEditorEngine::OnAllPIEInstancesStarted() is a virtual function that gets called when launching Play-in-Editor. It can be overridden if the game project chooses to introduce a subclass of U ...
Multicast RPCs may be sent to clients in a different level with Replication Graph
UE - Networking - Jan 20, 2026UReplicationGraph::ProcessRemoteFunction does not check if the client has the same loaded world as the server when sending a multicast RPCs. For actors that are persisted partway through a seamless ...
Material Analyzer misreports static params for Material Layers
UE - Rendering - Architecture - Materials - Jan 20, 2026When analyzing materials that use Material Layers, Material Analyzer reports that multiple Material Instances “share the same static parameter array” and therefore recommends reparenting so that onl ...
[Enhanced Input] The action instance data is incorrectly reset when you call "Add mapping context" on the same mapping multiple times
UE - Gameplay - Input - Jan 16, 2026This is somewhat related to [Link Removed] Closed and was brought up by a [Link Removed] Setting the CVar input.bRespectIM ...
Clearcoat material behaves differently between 5.5 and 5.7
UE - Graphics Features - Jan 16, 2026Starting with Unreal Engine 5.7, specular reflections on clearcoat Materials are less pronounced. Unreal Engine 5.5 tests performed on //UE5/Release-5.5/, CL: 41545209 ...