OK, thank you for your replies. So it seems, it is all fine with the mod pack.
@ Aslain:
Avast says there is no treatment found, but it will not open some files (like the skin-file of the Tirpitz, mask.dds files) because it says, that they are decompression-bombs (AVAST code 42110).
Are they maybe the reason of the detection in the smart screen filter?