FString.Mid doesn't react appropriately when given negative values for the Count variable

UE - Foundation - Core - Jul 16, 2015

If you use a 5 character string (hello) to call the Mid function and provide 0 for start, -1 for count, it'll give you the entire string. This should either return an assert or treat all negatives a ...

BP - Editing defaults on a nested subobject of a component inherited from a native parent class won't preserve those defaults when the BP is instanced.

UE - Gameplay - Components - Jan 19, 2017

I think the issue is that in GetInstancedSubobject() (CoreNative.cpp), the following bit of code is not considering that the instanced subobject might be outered to another instanced subobject withi ...

Crash when adding Actor Array Element to a Sequencer Event Struct

UE - Anim - Sequencer - May 25, 2017

Crash when adding Actor Array Element to a Sequencer Event Struct Error message: Assertion failed: 0 [Link Removed] [Line: 56] Source Context: 42 N = FName(*StringName); 43 ...

[CrashReport] UE4Editor_UnrealEd!UEditorEngine::CheckForWorldGCLeaks()

UE - Foundation - Core - UObject - Jun 29, 2017

This is a common crash occurring for users in 4.16. It is spread out among around 60 different CrashGroups in CrashReporter, because every case has a slightly different callstack. This appears to ...

Editor crash when using Animation BP pose watch

OLD - Anim - Apr 7, 2020

We encountered a crash when using Anim BP Pose Watches to inspect poses on actors in a PIE instance. Specifically it seems ending the PIE session while the Anim BP is still watching the actor in the ...

YCoCg to sRGB?

UE - Niagara - Rendering - Mar 20, 2024

Both the material and the Niagara compute shader use the same function to interpret the YCoCg color data, but the Niagara compute shader returns an incorrect color. Also found on CL: 32347737 in Re ...

Crash when changing r.MaterialQualityLevel when FastGeo plugin enabled in cooked build

UE - World Creation - Worldbuilding Tools - Sep 5, 2025

The engine crashes when the r.MaterialQualityLevel is changed in a cooked game that uses the FastGeo Streaming Plugin. The crash doesn't repro with the same steps in Editor, just in a cooked build. ...

AI Pawn Sensing component cannot see and hear at the same time

UE - AI - Mar 12, 2015

Hear events are never fired while See events are fired. They are mutually exclusive, with See events taking priority if both happen. ...

Using "Play Animation" node, if current animation has a looping timed particle it will continue playing

OLD - Anim - Jun 24, 2016

Calling "Play Animation", if current animation has a looping timed particle it will continue playing ...

Cursor Overlap events don't work on characters

UE - Gameplay - Sep 4, 2015

Setting up mouse over events for a character do not trigger. ...