Sometimes when you lag the restrictions about a party you create gets lost although the menu says they are set.
For example you create a party only for friends but they can't join saying its a closed party. it works again if you disable and reenable the setting again.
Can't join a party sometimes
Dom, 08/25/2013 - 14:04
Blue-Panther
I believe I have seen this when in mission lobby only, when you move on to the first floor of the mission they can join at will.