Main quest disappearing, can't get to New Game+

I'm having problems concerning the mode New Game + in Torchlight 2. I would really like to proceed to that mode and or to Mapworks, but it seems that every time I go to The Minehead or defeat the final boss (Netherlord), the main quest disappears and then you're just stuck at the game. I've tried different characters and still end up with the same problem.

I already finished all quests main or sub but still talking to Felicia or to the robot leading to Mapworks won't do anything. I'm playing v1.16.5.3 and I'm only playing single player mode game.