Unreal Engine Issues

Plane Constraint Normal is not Properly Reset

In the Character Movement Component, setting the Plane Constraint Normal to a value other than default, and then attempting to change the value back to the default does not revert to the default val ...

Linux: async loading code crashes when memory pooling is enabled

The reasons is a bad interaction between FIND_MEMORY_STOMPS code in AsyncLoading.cpp and memory pooling. Async loading will set PrecacheBuffer to read/only and will never reset it back, expecting ...

Mouse is not captured when switching between clients when running PIE

If the user launches multiple clients with PIE, the mouse will only be captured by the last client launched. If the user Alt+tabs to another window than the mouse will not get captured and they will ...

Null Material Layers in Material Instances cause Opacity Mask and WPO to break on Nanite Meshes

When a Material Instance is loaded that has a nullptr layer in StaticParametrs.Materiallayers.  The Material Instance will create it's own CachedExpressionData but the ConnectedParameterMask will be ...

Media framework doesn't play back in DX12

Crash When Raycasting Against Mesh With Multiple Materials

When using a raycast trace against a blueprint that has a child component with multiple materials will cause the editor to crash after a few times. This will not be an instant crash, but requires th ...

For a TMap with C++ enum keys, deleting and re-adding a map entry in the Editor can corrupt the map data.

When adding an entry to a TMap using UE's property editors, in most cases the new entry comes with a default-initialized key (if such key already exists, the insertion fails). The case of a UENUM de ...

Directx12 crashes with OOM

In editor, when running a task that does not issue a BeginFrame/EndFrame for a long time, the GPU will eventually run out of memory.  See UDN: https://udn.unrealengine.com/questions/431450/directx1 ...

FBX Scene imports with an addition Scene Root in the Hierarchy

There seems to be a second Scene root being created when importing an fbx scene. Something of note is that in the scene import dialogue we only see one "RootNode" listed. This has been found to occ ...

.mp4 videos are not playing on certain mobile devices

When launching a project with a video in it on an Android or iOS device, it either will work or it will not work. I believe this is due to the OS version of the device, but it may be related to the ...