I'm getting something odd happening with walls in 5.5 that doesn't happen with the same .stl files in 5.4 ...
At irregular intervals some layers are 'all shell' instead of using inner walls. Sometimes just a single layer, sometimes a bunch of layers together. This results in some visible differences in the printed surface (along with slightly slower print times). I've tried changing any settings I thought might affect this but not had any luck yet.
Full_Coin.3mf
Full_Coin.stl