My hullbreaker isle Kraken boss glitched out on me but not my party members. One of the tentacles stunned me (which is normal) and threw me into the water (not normal...). However, my party, who I am sure thought I was nuts, could see and damage the boss just fine, and said that on their screens I was standing on one of the platforms the whole time lol

Here are some pics of the interesting glitch :P