I posted in Talos's forums about the rock2_qnd issue (wasn't aware it happened with other maps too). Nostromo said he'd re-download and replace the version currently on the server, however I've been unable to try it out since he did so :/
As soon as I get chance to, I'll try it out.
As for reasons why this happens, not a fucking clue :/. Possibly related to the old 'map differs' problems that seemed common pre-2.0? (if that was really a problem, and not just idiocy?
)