Have you made sure there is nothing touching it anywhere?
Or Maybe a new exhaust and making smells that come across as rubber to you?
Only thing I can think of.
Bike maybe running rich.
I've checked and the only thing I can see close to the exhaust is where in the inside of the tail fairing wraps around the exhaust, but none of it's touching. And even if it was, I would think it would be more of a burning plastic smell, as the very tail of the tail fairing is just black plastic.