Unfortunately, the first and second bosses are noticeably harder than the third or fourth, which prompts people to leave quicker if things go south. To be fair, this tends to ease out once more people are willing to join in progress but I'll admit, I've noticed people bail after just a single wipe more so than back in Dun Scaith. Frankly, it's why I think the penalty shouldn't just be if one person leaves but up to at least three per alliance. What usually happens is one bails, then a bunch jump ship since they can immediately requeue.