Wow! Did you purchase them from a golf shop or second hand or on-line? My guess would be that some sort of chemical was used to remove stickers/labels and it damaged the finish to the chrome, thus allowing that area to rust. I could be wrong but that's what it looks like from the picture being that the rust is confined to just one concentrated area. No way to reverse it now, the chrome has already been compromised. You can use steel wool to make it look better and keep them oiled but they still won't match the rest of the shaft. Sorry to see this.

Only time I've seen a shaft rust was at the tip/ferrule from dunking head in the club cleaner. You only recourse is too reshaft.

I know the shafts on counterfeit Scottys rust almost instantly. That would be something that would raise a red flag for me with these. I honestly can't imagine what could have caused this normally.

Andrew, how old is your bag? Are you sure that's rust and not the bag dividers leaving sticky wear on the shafts? Had the same stuff on graphite shafts and was able to clean it off. Just a thought.