So now I found time to reflash my phone, but the results aren't as expected:

1. I reflashed with 20.2010.36-2 eMMC and complete and the lens/camera app worked like charm
2. I installed CSSU and had the same problem again. No reaction on lense opening
3. I reflashed again, but the problem still persists, even without CSSU

Any ideas? I also tried to remove battery before flash, so there should be a full factory reset, doesn't it?