FileSystemDerivedDataBackend may output a corrupted access log

UE - Foundation - Core - Derived Data - May 20, 2021

This problem is caused by the AccessLogWriter has not been flushed at the termination. The following workaround flushes the Writer.class FFileSystemDerivedDataBackend : public FDerivedDataBackendInt ...

Crash when a Deferred Decal (Translucent) base material has a Nanite Override (Masked Surface) Material and the mesh has Nanite + Ray Tracing enabled.

UE - Graphics Features - Ray Tracing - Aug 14, 2025

A crash occurs when Nanite override material instance is used in a project with Ray tracing enabled where: 1 The Material assigned to the static mesh uses Deferred Decal / Translucent and the Nani ...

Collision channel settings are not recognized in Standalone

OLD - Anim - Oct 18, 2017

Object instances that override the parent blueprint's collision settings are recognized in PIE but ignored in standalone or when running from the command line with -game NOTE: This appears to only ...

The 'Set Constrained Components' node doesn't set the physics constraint components correctly if used in the Construction Script

UE - Simulation - Physics - Jan 20, 2015

The 'Set Constrained Components' node doesn't set the physics constraint components correctly if used in the Construction Script. ...

Blueprint enum-to-string node returning inconsistent results across platforms

UE - Gameplay - Mar 5, 2020

Converting a C++ enum to a string should be a consistent result, however when running in the editor it returns the display-name value instead of the index value. This prevents C++ UENUMs from being ...

A crash can occur when multiple Actors are spawned/destroyed simultaneously with each one loading an asset.

UE - Foundation - Core - Jan 6, 2017

A crash can occur if multiple Actors are spawned/destroyed simultaneously, with each Actor loading an asset when it is spawned. This does not occur 100% of the time, but it does occur quite frequent ...

The Sorting Issue Between Height Fog and Transparent Objects

UE - Graphics Features - Aug 21, 2024

When a LocalFogVolume is used with ExponentialHeightFog, it does not correctly fog translucent objects. ExponentialHeightFog and Volumetric Fog from a LocalFogVolume both correctly occlude transluc ...

Any Alpha value set in a FLinearColor used to draw a line on a Canvas HUD is ignored when the line is drawn

UE - Graphics Features - Apr 21, 2015

If an Alpha value is set in a FLinearColor that is used to draw a line on a Canvas HUD, the Alpha value is ignored when the line is drawn. A comment in BatchedElements.cpp indicates that some legac ...

Hot reload fails in 4.16 projects that were upgraded from 4.15.

UE - Foundation - Cpp Tools - Hot Reload - May 16, 2017

This issue appears to be a continuation of [Link Removed]. Hot reloads work successfully in projects that were created in 4.15 or 4.16 and are still using the same Engine version that they were crea ...

Damping is handled differently at lower frame rates

UE - Gameplay - Aug 3, 2016

Damping is handled differently at lower frame rates. Slight changes in damping at lower FPS (25) drastically effects objects and isn't applied in the same way as at higher FPS (60) User Description ...