End dungeon dealing 0 damage indeed based on the rng of dungeon generation. If there's no clear path towards exit, it's PITA to complete. However, if there's under leveled character that have the goal, I say that's free xp. My verdict: maybe good for early game where there fewer chance of enemy room, but more frustrating toward more dangerous area.
Either that toggled, remove entirely, or community just shrug and bank the goal for cheeky free points.