Unreal Engine Issues
Unreal Engine Issues
FInstancedStruct member uproperties are not cached when "Generate Optimized Blueprint Component Data" is enabled
UE - Framework - Blueprint - Nov 18, 2025A licensee has encountered an issue where their FInstancedStruct isn't being gathered into CachedPropertyData when "Generate Optimized Blueprint Component Data" is enabled. The changes in [Link Remo ...
Instanced Actors: Moving element in editor is not undoable
UE - Engine Scaling - Mass - May 30, 2026Context Instanced Actors can be moved by unchecking Lock Instance Locations on an IAM, and double-clicking into the actor → comp → instance to select an instance. Problem Moving an IA via the giz ...
Crash when creating new projects or converting copies of old ones in Japanese
UE - Editor - UI Systems - Slate - Dec 4, 2014There's a crash in FCharacterList::GetKerning() when using the editor in Japanese that is apparently fixed in one of these three changelists: CL# 2370014, 2370050, and 2370040 But they were not ...
Blueprint 'Select' node: nodes connect to all input pins are evaluated while only one input is needed
UE - Gameplay - Blueprint - Aug 15, 2015Originally marked Won't Fix in 2017. Issue reopened on May 1, 2024. All inputs of a Select blueprint node are evaluated, even though in the end only one value is selected. This is wasteful work. ...
Replace Reference feature is not replacing textures with new selected texture
Tools - Jan 4, 2017Workaround:Open M_TableRound, move a node. Save the MaterialReopening the project seems to fix the issue Replacing the reference of the deleted table texture is rendering default material. Note T ...
CCD can produce incorrect results at low frame rates
UE - Simulation - Physics - Feb 27, 2019The attached project has a fixed frame rate of 30fps with a simulating CCD cube above a with a full restitution floor. The cube has an odd rotation, such that it impacts the floor at a single point ...
Rect lights cause visual noise on the light rendered when using raytracing
UE - Graphics Features - Lumen - Nov 12, 2019Rect lights cause visual noise on the light rendered when using raytracing. It is easier to see when you get rid of all other light sources in the scene. I have attached an example project. This se ...
Undo and ConstructionScript break the AttachChildren array
UE - Gameplay - Components - Nov 14, 2019Undo fills AttachChildren array with null by the undo serializer. After that, a construction script tries to remove child components from parent component's AttachChildren but it can't find its poi ...
TMap Contains Node Returns False Incorrectly Under Specific Circumstances
Tools - Nov 20, 2019The Contains node doesn't return an existing row from a data table under specific circumstances. This didn't occur when the struct the data table is based on was made via blueprints or there are mor ...
Changing "Coordinate Light Map Index" When "Generate Lightmap UVs" Is Enabled In A Static Mesh Crashes Engine
Tools - Dec 31, 2019When altering "Coordinate Light Map Index" in a static mesh when "Generate Lightmap UVs" is enabled in LOD 0 the engine will crash or "Coordinate Light Map Index" will be set to 0. A demonstration ...