Please try to give more detail. Does it happen the second that the bonus map appears? Do you d/c to the login screen, or out of the game? Do you get an error message? Does it happen every single time?... etc...
Of course~ it happens once someone hits a box and yes, it has happened every time. Everyone disconnects entirely out of the game. There is indeed an error message (can't remember what it says). If we do GPQ later on and it happens again I will be sure to get a screen shot for you.
I believe the bug you are referring to is when multiple players break open the same box at the exact same time - this has a chance to disconnect everyone on the map. There is not too much we can do to fix this so I can only suggest that you try to get the people in the PQ to open their own boxes.
The first PQ we did, everyone did break the same box. The second PQ, everyone broke different boxes. If not, some just stayed still for eveeryone to 'go crazy' with the boxes. We'll try it again later and I'll be sure you update you if it happens again. Thanks for your time!