I've done two Joker Poker backglasses, and the really rare Asteroid Annie glass when it started to de-laminate. These were maybe three years ago, and they remain very much intact.

I wonder if a difference in the inks used between manufacturers might have something to do with the messed up one? What game was it from? I can imagine a Williams one disintegrating, the late 70's glasses seem to really loose their ink easily, could have been that for example.