Noisy KK MK2 S88 keyboard

Hi, my KK MK2 s88 keyboard is very noisy. The noise occurs on the release of the note when it hits back the frame. Does that noise on all the keys. Of course, if you play in a band or a GIG this may not be an issue but when it's used in a studio environnement it becomes very annoying. It seems that the felt strip that is designed to damp the noise when the key hits the frame isn't thick enough and therefore is inefficient. Has anyone noted the same issue and is there a fix for that?