Flood mode mid-game joining problem.

Me and my friend been playing Halo 4 on flood mode, and were people can join mid game which will cause problem’s in the match which your teammates would have red on them. We went to kill them and though they were survivors but we got betrayal’s instead and got booted out of the match cause of the glitch for people joining mid-game. I believe flood mode shouldn’t have mid-game joining.