The slide has to come in far enough to allow a good fit to the seals. I don't know how your island is fastened, but is there a chance it may have moved. This just really isn't making sense. If the fridge isn't hitting against the island, when fully retracted, it is not a real issue, but rather an inconvenience.
Slides can be adjusted, for small corrections, but does not seem to be the problem IMHO.
Jerry