I had a few pairs of Jesters do this really badly, fortunately they were warrantied but I eventually gave up and went to a less-poorly-designed binding. Virtually every pair of early Griffons/Jesters I've seen that has been ridden hard has this issue to some degree. Once it starts slopping around it progressively gets worse and worse until your binding is like a bobble-head and won't hold the toe in properly any more. The later model has been changed to have a flat part around the base of the "pylon" assembly which reduces (although doesn't completely prevent) this from happening.
Once they go, they're f*cked. I suppose you could load the hole that the pylon inserts into up with epoxy or similar? Not sure how long that would last, though. Otherwise just keep skiing them, until they get really, really bad they'll still hold you in fine, they just make awful noises as your boot bounces up and down in the toe.