Today, I finished Prison of Elders at level 32 and after 1+ hours of playing, I got kicked out of the fireteam. Just before the chest. I couldn't rejoin the fireteam either, because it was set on private and the player deleted me from PSN. I thought I could just reconnect and open the chest by myself, right? Unfortunately, that was not the case. I had to start all over again, from round 1. Pretty unfair if you ask me. I don't really know if this is a common way for idiot players to just invite their friends into their fireteam, for "free loot" or if it is possible to increase their chances for good stuff when they open the chest by themselves. Anyway, Bungie should take care of this. A few friends experienced the same thing. Make a reconnection right at the chest possible, disable booting people from fireteams (at the chest-checkpoint) or hinder the remaining players from opening the chest.