I purchased the S80 2 weeks ago. While I am enjoying playing it, I have noticed that while playing the keys, there seems to be a noise like crackling paper between the keys. I've noticed this on both the white keys and the black. I also can see that there is something white between the keys that seems to be rubbing together when I depress them. It is not a real loud noise, but it is annoying to me as the musician. I don't know that the audience is able to hear it, but I certainly can. Is this something normally associated with this keyboard, or should I return it to the store where I purchased it and get another one? Maybe it's something that is normal with all electronic keyboards? I'd really appreciate any ideas as soon as possible. Thank you very much for your help.