Its not just Yamaha, We have found that it mostly happens in bikes where the rider is trying to shift too quickly without the proper amount of force. or as said clutch less. My 08 fz6 has 11,000 miles on it and has never had a false neutral. It is mostly due to rider error or abuse. I have also found some people ride with their foot on the shifter and don't realize it. This also causes premature wear and abuse.
This is exactly why it happens... :thumbup: :thumbup: :rockon: