UE 5.3: Issues with packaged game: broken nanite landscape and shadows

I’m almost afraid to ask, but did you guys find a solution?
I tried to package my projecty when I moved it from 5.2.1 to 5.3.1 and in a packaged build without Nanite enabled my whole LAndscape is gone…
Landscape Splines still exist. but no Landscape… No idea what’s goign on…