Stuck on black screen after completing mission

[Misoneist]

After completing 20 minutes of survival in the void the party extracted. After getting the extraction cut scene my screen went black but I still heard mobs attacking my warframe. Hitting escape gave me the option of abandoning the mission and showed I was alone in my party. When paused I could see the outline of my warframe. When I unpaused, the mobs I couldn't see continued to attack me past the point I should have gone down. I was still able to fire my primary weapon but couldn't use abilities. The other odd thing was that I thought there were originally 4 people in my party but when I paused, it showed only 3 had been. I didn't want to lose my loot or levels but wasn't sure how to leave. I ended up quitting the game with task manager. I just started warframe back up and it looks like all of my progress was lost. No affinity or items.I'm going to run it again and will report if it reoccurs.