Yes, everyone is in the party. Tried restarting the party, converting to raid, relogging, rebooting, none of that worked. It might have something to do with flagging, as it happened right after a HHM run and got into some scuffles outside, but I'm on a pvp server so I don't know much about pvp flag setting and all that. It's always on for me.

What did fix the problem was entering Heroic Gundrak. Weird stuff.