King in the Mists getting perma stuck in 2nd phase

I just did the King in the Mists pinnacle boss on difficulty 2 and right after completing the labyrinth phase which was extremely shorter than usual, the boss just got stuck in the top left corner of the boss arena. After a few seconds the boss morphed into his 2nd phase form and then just stayed in that place indefinitely, while all the other mechanics(tornadoes, blood boils, frogs) were running through the arena. The only solution was to just reset the boss and lose a portal because of this bug.