Unreal Engine Issues
Unreal Engine Issues
Incorrect usage of FText in EnsureMsgf does not trigger a compilation error, leads to crash in shipping
UE - Foundation - Core - Mar 1, 2018Using incorrect formatting in FText does not cause compilation errors in EnsureMsgf as it does in other functions such as UE_LOG. This causes crashes to sneak through such as a crash on ensure when ...
Collision problem in nativized blueprint
UE - Simulation - Physics - Jan 29, 2019Issue reported by one of our licensee on the Japanese UDN https://udn.unrealengine.com/questions/480660/view.html ...
Instanced static meshes fire an erroneous performance assert about loose parameters.
UE - Graphics Features - Sep 4, 2019"This ensure is intended to catch regressions where rendering programmers add a loose parameter to LocalVertexFactory, breaking dynamic instancing on regular static meshes. InstancedStaticMeshes c ...
Setting Fullscreen Mode to "Fullscreen" results in Crash when using 4.23 from source
UE - Rendering Architecture - RHI - Oct 11, 2019Changing the screen settings to Fullscreen through code or blueprints results in a crash. This only happens in the source version of 4.23 and does not occur in the binary version of 4.23. I have att ...
Spline Mesh Collision doesn't work in packaged game when spawning them at runtime
UE - Simulation - Physics - May 18, 2020Spline Mesh Components lose their collision in a packaged game when spawning them at runtime, or modifying them via 'Set Start and End' function at runtime. ...
Show Flags are changed to the state that they were set on editor startup when switching to a different level
UE - Graphics Features - Jun 15, 2018Show Flags are changed to the state that they were set on editor startup when switching to a different level It appears that the state of Show Flags are stored in the editor on shut down, this is c ...
Inconsistent media texture new style output state across the engine
UE - Media Framework - Jun 20, 2023A simple search for `NewStyleOutput = true` will reveal the many instances where this flag is already forced on, including media plates and media bundles. This however means that we have incompatib ...
Light Leak Issue in Modular Buildings (Lumen HZBTraversal)
UE - Graphics Features - Lumen - Oct 14, 2025Starting in Unreal Engine 5.6, disabling "r.Lumen.ScreenProbeGather.ScreenTraces.HZBTraversal" can lead to light leaking between adjacent or overlapping meshes. Also tested on Release-5.6, CL: 4523 ...
Subobject ComponentClass overrides cause failing assertions due to UObject reconstruction on AsyncLoadingThread
UE - Framework - Blueprint - Dec 19, 2025Context The blueprint editor allows you to override an actor component's class in derived blueprints (component details panel -> Component Class). [Image Removed] Problem When a blueprint and it ...
Packaging a plugin from Plugins Editor UI wipes the target folder before packaging
UE - Foundation - Cpp Tools - Plugin System - Sep 23, 2016"Package Plugin" from Plugin Editor UI will wipe the target folder’s contents first then populate it with plugin files. User was expecting “Package Project” like behavior: Create a new folder in th ...