Regression with RecomputeTangents on SkeletalMeshes in 5.6

UE - Graphics Features - Jul 21, 2025

Licensee noticed a regression in 5.6 where the non-masked recompute tangents option doesn't work anymore. The option is called "Enabled with no mask" in 5.6 but "All" in 5.5. Under the hood, this se ...

Unable to change Actor Coloration View Modes in PIE

UE - World Creation - Worldbuilding Tools - Jul 20, 2025

When in PIE changing Actor Coloration view modes from the viewport visualisation mode [Liit] -> [Actor Coloration] -> ... Does not update correctly when switching view mode and sometimes isn't corr ...

Enabling Strip Source Data On Cook on Geometry Collection is also stripping the Anchor flag of cooked assets

UE - Simulation - Physics - Jul 20, 2025

Enabling Strip Source Data On Cook on Geometry Collection (GC) is also stripping the Anchor flag of cooked assets. The licensee has reported that once they do a build the Anchors disappear and GCs t ...

Crashes after destroying a skeletal mesh attached via socket name (not bone name), the destroyed mesh remains welded.

UE - Simulation - Physics - Jul 18, 2025

On welding physics bodies during primitive component attachment, UPrimitiveComponent::WeldToImplementation() calls GetRootWelded() and then GetBodyInstance() on the returned root. This searches by b ...

Soft angular constraints solve velocity like hard constraints

UE - Simulation - Physics - Jul 17, 2025

Soft angular constraints are solving velocity like hard constraints. Instead of swinging back and forth, the affected body just snaps to 45 degrees. Check the steps to reproduce for more details. Th ...

Structured log automated decimal number tests fail in languages / cultures that use commas instead of periods

UE - Foundation - Jul 17, 2025

The following Localisation Tests in "Engine\Source\Runtime\Core\Tests\Logging\StructuredLogFormatTest.cpp:275" TestLoc(LOCTEXT("Float", " {Float} "), ANSITEXTVIEW(R"(128.25)")); TestLoc(LOCTEXT ...

Enabling Substrate causes MaterialGraph node previews to render black

UE - Graphics Features - Substrate - Jul 16, 2025

Node previews in MaterialGraph with Substrate enabled render solid black in 5.6. The latest 5.5 engine does render previews correct with substrate enabled. ...

Mover standalone backend allows non-persistent sync structs to carry over between frames

UE - Gameplay - Player Movement - Mover - Jul 16, 2025

Only certain sync state structs are intended to persist between frames. These are configured via MoverComponent's PersistentSyncStateDataTypes array. There appears to be a bug in the way the standa ...

Niagara Regression - Looping particle with Spawn Burst Instantaneous on time 0.0 flickers for a frame between loops

UE - Niagara - Jul 16, 2025

Note: This worked correctly up to UE 5.4, but repros from UE 5.5 up to mainline latest. If a Niagara Emitter is set up with "Spawn Burst Instantaneous" on time 0.0, and the spawned particle(s) have ...