There is one exception, which is that it is still possible for PC players to glitch into console lobbies. I saw a recent screenshot from an accusation of a PC predator playing in a low level console lobby - the player clearly had a PC logo next to their name. I'm sure the accuser checked their gamer tag in the leader boards as well. I mean, it's not happening all over by any means, but it is possible. That player would most likely have been using cheats as well as getting into a lobby they had no business being in. They appeared to be there to boost their squad mates.
IN NO WAY am I suggesting that this may have been the case in OP's video, however. It's just a spectate bug as you said.