Unreal Engine Issues
Unreal Engine Issues
FAnimationRuntime::BlendPosesPerBoneFilter() causes an assertive crash when Skeletal Mesh LOD is changed
UE - Anim - Runtime - Nov 1, 2023The crash occurs from "check(BoneBlendWeights.Num() == NumBones);" This crash occurs when the following conditions are met;The skeletal mesh LOD is changed.The number of bones is difference between ...
Crash when Live Coding is triggered after engine source edits Blueprints using ChildActorComponent
UE - Framework - Blueprint - Nov 28, 2025After editing engine source files and triggering Live Coding, derived Blueprints that inherit from a Blueprint containing a ChildActorComponent cause UChildActorComponent::Serialize to run on a Live ...
Content is Missing from Cook and indeterminism: StaticMeshComponents in Blueprints that copy data into themselves from StaticMesh have indeterminism due to StaticMesh not yet finished loading, postloading, or building
UE - Foundation - Nov 12, 2025Content is Missing from Cook warnings are warnings reported at the end of cook phase of a project's data build. They report that data used by a cooked package will not be available at runtime. This ...
Light Function and World Position in 5.4
UE - Graphics Features - Nov 4, 2024When rendering a Light Function into the Translucency Lighting Volume, the World Position Material Expression returns the position relative to the Camera (unrotated), not the World. This can be mor ...
Input Mapping Context entries can get into a corrupted state when swapped with another entry that has a Combo Trigger.
UE - Gameplay - Input - Aug 23, 2024This behaviour was working correctly in version 5.3. This issue happens inside an InputMappingContext DataAsset from the EnhancedInput system. We need at least two mappings entries. One of the entri ...
UAnimNotify::Notify not called during USkeletalMeshComponent interaction with UPhysicsControlComponent when PhysicsBlendWeight is zero
UE - Anim - Synthesis - Physics Control - Mar 30, 2025UAnimNotify::Notify not called during USkeletalMeshComponent interaction with UPhysicsControlComponent when PhysicsBlendWeight is zero. The licensee has provided his analysis of the code: If USkelet ...
When r.SSR.Stencil is enabled, there is wrong logic observed.
UE - Rendering - Graphics Features - Dec 19, 2025When r.SSR.Stencil is enabled, the areas with high roughnesss are not discarded and Unlit materials are incorrectly handled. See the linked EPS case (Additional Info URL) for a full explanation of ...
Blurry RVTs after camera jump
UE - Graphics Features - Aug 7, 2025When using Runtime Virtual Textures (RVT) on landscape in UE 5.5+, nearby tiles may remain blurry (low-resolution mips) after launching PIE or making large camera jumps (e.g. via bookmarks or viewpo ...
Large Landscapes cause long PIE start time delays
UE - LD & Modeling - Terrain - Landscape - Jan 29, 2020These delays appear with large Landscapes (for example 8029 x 8029) . The delays only start occurring after the level is saved and reopened. After which PIE start times will be 5 to 15 times longer ...
Blueprint Struct Issues - Data table wiped data
UE - Gameplay - Blueprint Compiler - Aug 19, 2024The user has come across various issues with using nested blueprint structs within a data table. The first issue relates to changing a variable in a child struct and setting it back then saving, cau ...