Mechagon dungeon quest disappeared


The “Operation: Mechagon - The Mechoriginator” quest just vanished from my quest log. I surely had it yesterday, and did the dungeon this evening being sure that I have that quest. After finishing the dungeon I headed to Prince Erazmin in order to turn in the quest, but the NPC didn’t have such an option. Now I can’t take it again neither can get the achievement for completing the storyline.

Did anybody have similar issue?