ApplyLocalExposure uses Output_ExtentInverse instead of Output_ViewportSizeInverse for bilateral grid UV

UE - Rendering - Graphics Features - May 18, 2026

The ApplyLocalExposureCS shader in PostProcessLocalExposure.usf computes UV coordinates for the LumBilateralGrid 3D texture using Output_ExtentInverse (1/RenderTargetSize) instead of Output_Viewport ...

[Enhanced Input] Chord trigger fails when its referenced action lives in a lower-priority IMC

UE - Gameplay - Input - May 18, 2026

Summary A UInputTriggerChordAction does not fire when the action it references (the "chording action") is mapped in a different Input Mapping Context with a lower priority than the IMC containing the ...

Twinmotion sign-in error when attempting sign-in inside app

TM - Core - May 18, 2026

Reported in SF [Link Removed] Attempting to sign into Twinmotion from within the TM 2026.1 editor results in a consistent sign-in error using the sign-in buttons. Initial sign-in during launch whe ...

iOS builds fail on Windows.

UE - Platform - Mobile - May 15, 2026

Loading Windows installed iOs mobile provisioning profiles fails at start of iOS build from windows machine. This due to a recent change that attempts to load PKCS12 from mobileprovision files. Thes ...

Imported Substance materials behave incorrectly when applying UV rotation

TM - Tools - May 14, 2026

Reported in SF [Link Removed] and on the forums at https://forums.unrealengine.com/t/substance-3d-materials-not-reflecting-light-properly/2718611 UV rotation behavior is incorrect for Substance mat ...

Visibility track key value is no longer the inversion of the bound bHidden property

UE - Anim - Sequencer - May 13, 2026

Regression introduced in UE 5.7. Works correctly in UE 5.6. Up to UE 5.6, the bool value written to the Visibility track's BoolCurve was the inversion of the underlying bound property (e.g. AActor: ...

Blueprints: ComponentClass override causes crash on loading maps with instances saved with base class

UE - Framework - Blueprint - May 1, 2026

Context In actor blueprints, you can change an inherited component’s class in the editor by selecting it in a child blueprint and changing its Component Class in the Details panel. Problem When o ...

Crash in FNiagaraEditorModule::PrecompileDuplicate() — null deref of Handle.GetEmitterData() in third "finish off the emitters" loop

UE - Niagara - Apr 30, 2026

Crash / null pointer dereference in FNiagaraEditorModule::PrecompileDuplicate(). File: Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Private/NiagaraCompiler.cpp Function: FNiagaraEditorModule::Pre ...

GetStaticComponentMaskParameterValue returns the value for Static Switch Parameter

UE - Rendering - Architecture - Materials - Apr 24, 2026

UMaterialInterface::GetStaticComponentMaskParameterValue gets the parameter value from the static switch list instead of from the StaticComponentMask list GitHub branch 5.8 still looks to have this ...

Landscape displaces after converting file to Twinmotion 2026.1

TM - Core - Apr 23, 2026

Reported in SF [Link Removed] The client has a file from Twinmotion 2025.2 that contains a sculpted landscape. When converting the file to Twinmotion 2026.1, the landscape becomes displaced from it ...