Crash occurs when a struct containing an instanced object property is used as the value for a TMap in a class that is subclassed in Blueprints

UE - Foundation - Core - Mar 23, 2017

Using a struct containing an instanced object property as the value for a TMap results in a crash if a Blueprint of the class containing the TMap is subclassed and the child Blueprint is opened the ...

Client crashes after second seamless travel when a blueprint manually placed in the world spawns a replicated actor

UE - Networking - Sep 19, 2019

When a user loads into a level that spawns replicated actors using manually placed blueprints twice using ServerTravel with Seamless Travel enabled it will crash. It looks like the engine can't find ...

Crash running construction script after compiling BP function library

UE - Gameplay - Blueprint - Sep 15, 2020

Editor can assert when changing the signature of an editor authored Blueprint Library Function (FuncA) if that function is called from a Blueprint Library Function (FuncB) via an actor's constructio ...

Inaccurate Panning on Tap Delay Submix

UE - Audio - Oct 5, 2021

The panning in the Tap Delay Submix Effect does not always match its assigned Pan in Degrees value. Specifically, the left and right side appear to be reversed on Stereo setups. In addition, in 5.1 ...

Cursor locks to ScrollBox in native fullscreen mode are locked in the wrong position

UE - Editor - UI Systems - UMG - Sep 17, 2024

When specifying a widget of a different size than the screen in FReply::LockMouseToWidget, the cursor is locked to a different position in native full screen mode. It appears that the window size n ...

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 ...

Calling UBlueprintMapLibrary::GenericMap_Find with a non-existent key causes a memory leak

UE - Framework - Blueprint - Apr 15, 2025

When Calling UBlueprintMapLibrary::GenericMap_Find with a non-existent key, the function construct the default structure in-place on the given pointer without destroying the object. This behavior ca ...

[AI] Debug Render Scene Proxy hits ensure for registering a delegate twice during level streaming.

UE - AI - Debugging - Aug 31, 2022

Description from licensee: We're seeing an ensure get tripped up in FDebugRenderSceneProxy that says "DrawDelegate is already Registered!". Debugging the issue, we have confirmed that the DrawDeleg ...

Merging Splines causes Engine to Crash in 5.1

UE - World Creation - Worldbuilding Tools - Merge Actor - Dec 15, 2022

Attempting to merge two spline actors causes the Engine to crash. This issue occurs with the Steps to Reproduce regardless if there are more branches added to the tree branch spline/enabled, and reg ...

Chaos : Rigid body sleeps when very small external force is applied by AddForce

UE - Simulation - Physics - Solver - May 25, 2022

When a small external force is applied to the rigid body, the VSmooth value is reset in the ResetVSmoothFromForces function. Since this function ignores the current velocity, a very small velocity ...