I have several dungeons completed on my travel list, but they are not going away or re-spawning after I complete them. Nor can I buy any more from Aliron.
A successor to first Strive For Power game, currently at alpha stage · By
I think that the game expects you to kill the boss with one team, and harvest with another -- it's the most efficient way, if you have the manpower and the gear for it. When you do it in one visit (with one team), as we all do in the early game, you reach this "oops! didn't think of that" state -- so no Forget Dungeon button for you :) .