Using ConstructorHelpers::FClassFinder in a GameMode constructor may result in a default value or crash if the level is reloaded multiple times.

UE - Gameplay - Oct 27, 2015

Randomly selecting a character class from the GameMode constructor using ConstructorHelpers::FClassFinder can result in default or null character being set when the level is reloaded. It appears tha ...

"Active" marker on shot track scales improperly when using Time Scale

UE - Anim - Sequencer - Apr 21, 2017

"Active" marker on shot track scales improperly when using Time Scale ...

SingleSampleShadowFromStationaryLights does not work in UE5 (when GPU-Scene is used)

UE - Rendering - Features - Shadows - Jul 21, 2022

The flag is not propagated in FPrimitiveSceneShaderData::FPrimitiveSceneShaderData and so is missing in GPU-Scene primitive data. Need to add: .UseSingleSampleShadowFromStationaryLights(Proxy->UseS ...

Server crashes when client connects after Server has reloaded a sublevel with a deleted actor

UE - Networking - Jul 13, 2017

UNetDriver::DestroyedStartupOrDormantActors maintains a list of deleted startup (and dormant) actors. This is used to notify clients that have joined the server of Actors that need to be destroyed ...

Out-of-Bounds Access During Partial Updates of ISMC Per-Instance Custom Data

UE - Rendering - Features - Jan 6, 2026

When using instance custom data values, removing an instance and changing the number of custom data floats in sequence can cause an array-out-of-bounds crash. The underlying arrays are not resized ...

Sequential Level Loading in Python causes Crash

UE - Editor - Workflow Systems - Apr 16, 2019

Loading all the levels selected in the Content Browser and running the aforementioned Python script causes the editor to crash Tested in 4.20.3 (CL - 4369336), 4.21.2 (CL - 4753647), 4.22 (CL - 5 ...

Low acceleration changes causes the object's velocity to nearly zero out.

UE - Runtime - Simulation - Apr 20, 2022

Low acceleration changes causes the object's velocity to nearly zero out. The range this seems to occur at for the Acceleration change is between the values of zero and approximately thirty. Repro ...

Client crash on seamless travel in DataReplication with lag

UE - Networking - Jan 11, 2016

When server traveling, client may crash due to lag while attempting to replicate object/property. ...

Assertion failed: PlatformNeedsExtraDeletionLatency()

UE - Rendering - Architecture - RHI - Mar 5, 2019

Animating a HISM along a spline when many other HISMs are present will result in a crash in 4.22. Confirmed in 4.23 MAIN @ CL 5291468 ...

Making changes to a Camera Shake while previewing the Camera Shake triggers a crash

zComponent - Archive - May 23, 2022

This is not a regression. Tested in //UE4/Release-4.27 CL 18319896  Making changes to a Camera Shake while previewing the Camera Shake triggers an Assertion upon compiling. ...