Mine is getting loose after 2 years of admittedly intensive use, to the extent that it fell off twice when picking the camera (after some warming and massaging, it would stick again, to a limited extent).
At the camera shop, they said the cause was the solvent-free glue allowed in Europe; Df sold in Japan do not exhibit that nasty behavior. I am a bit surprized by the explanation, since the Dfs are anyway assembled outside Europe, right?
Moreover they said that I could return the camera to get it serviced. But I do not want to part for two weeks from the camera that accompanied every single step I made since May 2014. Call that a fetish if you like, but in fact I think it is a bit ridiculous, there must be a simpler way. Maple syrup? too sweet. Neoprene glue? is probably going to dissolve the rubber. Give up the rubber and glue some gaffer tape instead? inelegant. Put double-sided adhesive tape to re-glue the rubber? but I do not know the best way to first get rid of the present glue.
Shto dyelat, as Lenin put it...