hi @JanHxH_de ,
In 5.2 It was Llighting of shadows really broken . I make the new versions of Luoshuang’s GPULightmass (LGPU) binary and I refused to make a 5.2 version, as it was so buggged. Therefore we went from 5.1.1 to 5.3.1/2.
See posts
Unreal Engine 5.2 Released LGPU reply
You need to go back to 5.1 version of project then convert to 5.3 and see if that makes a difference.
I am not sure if 5.2 project work gets to 5.3 correctly only tested 5.1 to 5.3
anyway baking and light shadows was really broken in CPU Lightmass, EPIC Lightmass and 5.2 LGPU attempt was never released.
Have you tried exporting assets from 5.2 to and importing them into a blank 5.1 and allowing the 5.3 convertor create them therefore avoiding 5.2 which also DX12 SM6 errors