I called for military aid and the allied drop pods came down next to a mountain. One of the guys apparently landed on a rock roof, which thereby collapsed. The guy then got trapped by collapsed rock which caused the whole group to leave the map immediately.
Suggestion: Allies shouldn't drop on rock roofs
I think they should preferentially avoid dropping on any roof, if there is an available spot within the drop radius.
If there is no such spot, they still need to drop on a roof.
Should be fixed in the next build. Thanks for reporting!