Both my birds had risers and no cable issues, aftermarket on my '97 and VFRs on my '01. Maybe there's some slack somewhere you can pull to where you need it? Maybe the cable is miss-routed?
It happened to me a couple of times. for me it was just a lazy left foot. It doesn't drop down 3 gears to the neutral position if finds a NEW neutral position between 5 and 6