[2019] Just joined into a match to see I have 3 other teammates. We ended up dying to another squad of 4.

We are sure it was just your team that suffered from this bug and you encountered a number of other duos at the boss. There are no sessions known to us where this bug resulted in more than one 3+ sized team. It's a fairly rare bug to happen as a consequence of the matchmaking system running into problems during team ID assignments. Will be fixed eventually.

On a different note, looking at the picture above: Force ghosts confirmed! :P