After stage 9 or so all 3 of my teammates left, i decided to stay because i had a built Mesa as my loadout which was basically a free infinite run and i needed more levels. Lo and behold, the host migration happens, but i end up in the same tile as the previous mission, with no mission objective spawning or showing up in the UI, it should have been a defense mission.
I had to leave manually and forfeit all my rewards after carrying my team for the better half of an hour this is unacceptable.