This has happened twice so far and stopped us getting rewards both times. First my friend lagged out and we wiped before we killed Skolas thinking he can rejoin in the PoE lobby. He isn't able to because the activity was too close to completion and there's no way we were going to try it with two; not to mention he wouldn't get his rewards for it either if we did complete it. We couldn't back out and use a checkpoint because PoE doesn't have them so we had to restart. Second one I lagged out AFTER we killed Skolas and wasn't able to access the chest to get the rewards when I tried to rejoin. The game needs to either remember who started the activity and let only that player back in after they disconnect/lagout (similar to the achievement requirements of flawless raider) or allow players to rejoin while the session is still in progress . The game ends 10 seconds after the chest is accessed anyway by anyone in the game, so cycling friends to get them rewards isn't going to be a problem. All it does is make those who have an internet drop feel cheated out of rewards.