I'm not sure how to properly articulate the issue, but here goes:

Twice now, our group has spent a Void Brethren Insignia III (yikes) and loaded into an Upper Hive map. About half-way through the map, the map becomes glitchy and team members teleport all over the place. When the mission is complete, the team teleports away, but the map doesn't unload for a loooooong time. Minutes. When it eventually does unload and we are back on the bridge, our invetory is all messed up. The levels we gained in the map are lost and the gear we picked up is gone, only to be replaced with gear that we'd gained at the end of the previous mission. Restarting the game returned some of the new gear, and repeated some of the previous mission's gear again. (It's kinda hard to tell exactly, but this is what it seemed like.)