Hey @Kavan - thanks for the report. This comes as a surprise as I was baking lighting and flipping project settings up until days prior to release… however, I was able to reproduce the issue and I have a workaround:
In Project Settings → Platforms → Windows → Targeted RHIs → Default RHI. Change from DirectX 12 to DirectX 11.
OR
In /Project/Config/DefaultEngine.ini, change DefaultGraphicsRHI=DefaultGraphicsRHI_DX12, to DefaultGraphicsRHI=DefaultGraphicsRHI_DX11
I’ve logged the issue and will try to get it hotfixed ASAP.