To friends in the community... yesterday I went through this, I was in a group of 3 players and it went wrong, the mission was level 5 to clean the Pop-N-Pills factory, the door button wouldn't open the door, I opened it with the pickaxe and I killed the enemies, however, the mission kept warning me that there were no zombies in the room, after a lot of research, I found this forum and as an alternative solution I took the reward ticket to compensate, but, before deleting the mission, I had an idea, what if did I break the button? Well, I simply solved the bug, broke the button, reset the zombies in the room, then eliminated them and the mission was completed.