When hosting a server from my arma 3 client, if I load a mission with more than one dot in the name, the game crashes.
The game does something to the effect of splitting the file name at the dots, selecting the first substring as the mission name and the last substring as the map, ignoring substrings in the middle.

eg:
repro.mission.vr
ErrorMessage: Cannot open file 'mpmissions\repro.VR'

See how it omitted .mission from the file name it tried to load.