nop head has to run stl through a 'canonicalization' script that sorts the triangles.
this should be an option available in openscad itself.
https://github.com/nophead/Mendel90/blob/master/c14n_stl.py
Want to back this issue? Post a bounty on it! We accept bounties via Bountysource.