UE5.6+ - Mutable - IDPrefix crash when combining Child Objects, Add to Mesh Component and Extend Mesh Section.

UE - Anim - Mutable - Jul 21, 2025

So the issue seems to be a combination of Add To Mesh Component and Extend Mesh Section. I've tried this in Epic Launcher 5.6, 5.6 in-house modified engine as well as ue5-main 5.7 from git (editor ...

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 ...

UMaterialFunctionInterface not being tagged as BlueprintType makes some editor scripting scenarios difficult

UE - Rendering Architecture - Materials - Jul 21, 2025

UMaterialInterface is BlueprintType, but UMaterialFunctionInterface is not. This makes it difficult to port some BP logic that works with materials to the material layer system. Crystal Dynamics wou ...

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 ...

Crash when travelling during ability activation when URL contains "#"

UE - Framework - Jul 18, 2025

This issue is related to [Link Removed], where the "?listen" option sent on the URL to clients could cause issues with RPCs being called locally during travel. The fix to remove the "?listen" option ...

Assets on paths with speed parameters are sped up in Path Tracer exports

TM - Rendering - Jul 18, 2025

Reported in SF [Link Removed] In Path Tracer renders, all paths with a speed component (vehicles, bicycles, custom) will render at an increased speed than specified in the exported render. This is ...

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 ...