Hi :-)
In my configuration and slicing with Skenforge I've discovered some bug. The bridge above the nut starts too low, so there's a gap just above the nut. This is a visualisation of this layer made under YARRH. Obviously it can't be printed properly
The solution is to make one more solid layer just above the nut, so the bridge will have no gaps.
Slicing with 0.3mm layer height, the same height set in M90 config. However I had no problems with 0.4mm when printing my first M90 ever.