Okay, I don't know if anyone post this yet, but the way to fix the Boss Mode Glitch is as followed: 1. Create a Boss Mode Room with a map that can go up to 6 players. (For example: Vladimir Castle) 2. Exit the room and the glitch will be permanently gone. Now the reason why you get Boss Mode Glitch is because you enter or make a Boss Mode room with a map that consists four players. (For Example: Al Hata) You don't have to make the room. If you are room master, all you have to do is switch the map to a map that can be played with 6 players. That's how you fix the Boss Mode Glitch.
There's people who get the glitch without ever coming in contact with BM doe. Thanks for guide. I'll try next time this happens to me1!!