Sometimes at Gollux Abdomen or Head maps, I get into a state where no skills or items work.
At Abdomen this usually happens as it dies, and leaves me unable to enter any of the portals to leave the map. The only thing I can do is click "leave" on the mini-map. When I am returned to the entrance map (Memories of the Heart Tree), the skill lock is lifted and everything goes back to normal.
At Head this usually results in my death, and then I am unable to respawn because clicking the button on the "you will return" dialog box does nothing. In this case even "leave" does nothing, and I am forced to exit the game. (Well, I suppose that if I wait for the timer to run out I will end up back in the Memories of the Heart Tree and back to normal, but relogging accomplishes the same thing, faster)