A major peril (if I remember correctly was "Shadow Binders") have showed up spawing some monsters which in the same turn were required by a tile we had just explored in the quest "Tombs of Kayladorn") . Due to the group limit rule we chose to remove the first group and replace them in the new room.
A bug appeared in the system since, because the new moster group were already in the monster list, the characteristics of the unique monster in the new monster group didn't appear. We had to resolve the problem quitting the campaign and killing the first group monster before re-exploring the new room but we would prefer this thing to not happen.
Edited by Gendalm