That would be great. The Game still runs and you are theoretically able to restart the mission but it's not playable due to the blur. I just uploaded a short Clip on my Dropbox, so you can see what exactly happens and maybe find a way to reproduce and fix it.
https://www.dropbox.com/s/ah00s5c9srdwvw7/BossBug.mp4?dl=0
Also, here's a little Picture how exactly we played the game. I think it is the way it's meant to be played :p
Greetings from a couple to the dev's! :-D