Same thing here; tried a bunch of different drivers, another pc, another project, even tried windows 11 to see if it happened there too… just a whole bunch of different things; and there’s no replication for the bug, it just happens sort of happens to textures and/or their mipmaps after a while on projects running D3D12.
At first i thought VRAM intensive projects might have something to do with it, but it even happened in a project that is absolutely not VRAM intensive.
Saving/refreshing the texture gets rid of it, but it’ll just happen again to another texture, the only way to get rid of it for a good amount of time is an engine restart.
No idea what causes this. Would love to officially hear from Epic on this issue.