blackstonekeep.com

Return portals after certain bosses have no dialog, so if you accidently click you just get ported out sometimes missing loot or even the boss itself. The ones I can think of are Agnar and Witch.

Yeah I have missed a few loot drops because a portal spawns too near the death of a boss would be better to have in my opinon a set place away from the possible death zone... Perhaps behind a door to a little room which opens only on death of the boss... So preventing one from stepping on the portal that spawns so near the death spot...

A dead dragon on a portal in Lost City causes the same issue. In fact, it is not very big problem, but, I think, every of us, who has good tradition to visit Lost City from time to time faced it, as minimum, once.