Ah see, I don't have test so I know very little about what goes on over there. In reference to going back an island I meant on the live servers. From what I'd heard, and from being in a broken invasion with the Keg Runners, invasions didn't start mass breaking till said Keg Runners showed up. From what I'd heard the Tuga invasions were doing ok till the Runners were suddenly released, so the natural assumption, for me anyway, is that it's the Keg Runners who started it. Maybe I'm wrong here, but it is just a theory.
That said, D has removed other non working items. For example, I sent in several bug reports when my pirates fell in the floor during the Barbossa cutscene where you get your pistol. What did D do? They shortened the cutscence, to exactly the spot where the pirates fall through the floor. I just figure, moving on from Tuga invasions was D's small way of saying, yup, it's broken.