Cannot change the Strength value on a Physics Constraint in the Viewport Details panel

UE - Simulation - Physics - Jan 5, 2017

Cannot change the Strength value on a Physics Constraint to anything other than the default value in the Viewport Details panel. When changed the editor will pause and replace the value with — This ...

Pre-UE5 serialized FVariant FVector data corruption when deserialized in UE5

UE - Framework - LWC - Jan 15, 2024

FVariant is a struct that implements a union of data types, including FVector. When assigning an FVariant an FVector value in engine versions UE 4.27 or earlier, the FVariant will deserialize incorr ...

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 ...

Child Actor Component Actor Duplicates and Persists After Play

UE - Gameplay - Sep 26, 2019

When an actor spawns another actor using AddChildActorComponent that comes alphabetically before it based on blueprint name it will spawn an extra actor that will persist when the scene is stopped d ...

Using a FormatText node with Specifier in the same graph as an empty Macro will freeze the editor

UE - Gameplay - Blueprint - Jun 17, 2016

Using a FormatText node with Specifier in the same graph as an empty Macro will freeze the editor. Not using the Specifier or deleting the unused Marco will allow the BP to compile fine. **Only rep ...

Integer Blueprint variables reset the Bitmask Enum setting when the Editor closes

UE - Framework - Blueprint - Feb 28, 2019

User created Bitmask flag Enumerators are not correctly stored and retrieved from Blueprint Integer variable settings. When the Editor is restarted the value of the Integer's Bitmask Enum is set to ...

Camera Movement is laggy while the mouse button is held down and ShowMouseCursor is enabled if there are AI moving

UE - Gameplay - Dec 15, 2015

Camera Movement is laggy while the mouse button is held down and ShowMouseCursor is enabled if there are AI moving. Stat Scene Rendering didn't show any jumps while moving the camera under these cir ...

PhysX Crash when spawning Instanced Static Mesh actors at Runtime

UE - Simulation - Physics - Destruction - Oct 13, 2015

Bug generated from crash reporter. This crash has been found in 4.7.6 and still occurs in 4.8.3 and 4.9.2 to users. One user in particular still, and he experiences it often. I have not been able ...

AMD GPU crash with "Video memory has been exhausted" error when increasing the World Partition world and using Water Body Ocean

UE - Graphics Tools - Terrain - Landscape - Dec 8, 2022

Current steps describe the problem related to "Video memory has been exhausted (#### MB over budget). Expect extremely poor performance" on the AMD video card. In this case, the steps cause the GPU ...

[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 ...