1. Create a Custom Arena (for this test let's say NDIsles)
2. Once loaded go to Staged Missions and select a mission (for this test let's say "7 minute ABS")
3. Load the mission.
4. Populate the mission.
5. Any attempt to join the Axis side of the mission will crash the Custom Arena. You get "Host Lost" and come back immediately and the arena is gone.
Note: No dmp file is generated, assuming it is a server-side issue. It does not appear to be specific to terrain or mission. Does it on everything I have tried. My stuff, or HTC's.