Arrays in UMaterialEditorInstanceConstant are not updated

UE - Rendering Architecture - Materials - Jun 13, 2025

Any UPROPERTY TArray added to UMaterialEditorInstanceConstant will not cause UI updates when elements are added or removed. This is caused by the custom validator created in FMaterialInstanceEditor ...

Nanite UV switch seams

UE - Graphics Features - Jun 13, 2025

Analytical Derivatives are not calculated properly when using UMaterialExpressionSwitch. Disjoint UVs in screen space result in large jumps in the derivatives, which can cause artifacts as the wrong ...

MRQ - MovieGraphEditorExample.py on_executor_finished_delegate not called in 5.6

UE - Anim - Sequencer - MRQ - Jun 13, 2025

From UDN: We are launching jobs using a modified version of MovieGraphEditorExample.py. In 5.5 everything works fine, but in 5.6 the on_executor_finished_delegate is never getting called when all th ...

Light Mixer - All of the Light Attributes disappear when you have Show Only Selected enabled

UE - Virtual Production - Tools - Jun 13, 2025

All of the Light Attributes disappear when you have Show Only Selected enabled. ...

Pasting a folder on the Outliner while LightMixer and ViewChanges windows are open/docked crashes the Editor

UE - Virtual Production - Jun 12, 2025

When both LightMixer and ViewChanges windows are open, pasting a folder into the Outliner crashes the editor. For more detailed steps, refer to the Steps To Reproduce section. This happens whenever ...

Dithered LOD transitions do not work when the camera's field of view changes

UE - Graphics Features - Jun 12, 2025

Dithered LOD transitions do not work when changing the camera's field of view and cause artifacts when both the FOV and camera distance to the object are changed simultaneously. ...

IsLocalController returning incorrect value when PIE listen server travels back to standalone map

UE - Networking - Jun 11, 2025

In this situation where the listen server travels back to a level without listening, IsLocalController can return the incorrect value. After the NetDriver has been shutdown and destroyed, the pawn a ...

bIgnoreAllPressedKeysUntilReleaseOnRebuild in Enhanced Input behaves unexpectedly during pawn possession

UE - Gameplay - Input - Jun 11, 2025

This is a speculative bug report from the user.  The fix for this is to re-do the work of 31224705 but in a better way. The "bShouldBeIgnored" flag is being overriden by the previous mapping's va ...

In editor, sub level instance's streaming state persists incorrectly after toggling Level Behavior without saving

UE - World Creation - Worldbuilding Tools - Level Instances - Jun 11, 2025

When adding a sub level with world partition streaming to a main level where the streaming is also enabled, setting* Level Behavior* of the sub level to Standalone, and saving the result, in the fir ...

Static lights become stationary after toggling visiblity of level in packaged build

UE - Graphics Features - Jun 11, 2025

In 5.5, there is a regression with baked lighting where static lights become stationary lights when a level is hidden and then made visible again. This happens in packaged builds and shows up as sta ...