I had a mission on a map called 'Big city' .. that's all there was for the name and the description of the mission. It's a map with a multi-storey car park / parking garage.
All but one of my soldiers was trapped in the dropship, unable to get out. The default ground 'level' appeared to be '2', instead of '1', I don't know if that was the issue, but none of the soldiers in the ship could get out. I tried changing levels too. When I selected level 1, the screen was black.
So, I had to quit out of the map.