Ive had it randomly and in random places whilst out exploring, never in a dungeon tho thank the gods, at first falling through the map was kinda funny but when you then have to run half way accross the map to get to the one spot you can get back onto solid land again in limsa it sorta gets annoying....tried all the fix ideas mentioned but nothing sticks for long.

Wouldnt surprise me if the reason they arent commenting is because they dont realise it is a problem....afterall its possible nobody has reported it outside the us/eu servers.