Cartridge alignment help.

First, make sure all alignment and setup parameters are correct, including VTF and azimuth as well as overhang/zenith. A slight inaccuracy in azimuth could cause this problem.

If that doesn't help then the JMW-9's rudimentary antiskate "adjustment" becomes a prime suspect. If inaccurate antiskating is to blame then left channel sibilance indicates a need for LESS antiskating force. Try unplugging your wire, allowing it to return to a neutral position and start from there. Increase twists one at a time. Make sure the wire is dressed so that it puts no sideways pressure on the arm anywhere across its arc.

If no happy medium can be found between too few twists and too many, you might consider buying the optional antiskate mechanism VPI now offers for your arm. I've read good reports about it.

BTW, what cartridge are you using? Some are better than others at tracking difficult inner grooves.

This is a tracking problem of your needle not following the grooves properly. The last few grooves are have less circumference in the record, so the track velocity is higher. Thus, it is harder to track the inside grooves compared to the outside ones.

This is tough to fix. Alignment is where you start, since this fix is free. Other options include replacing the cartridge with one that will track those grooves. Tonearm positioning could also be off a touch. About the only thing that won't cause this is the turntable itself. Also, consider a stylus replacement, too.

I feel for ya! Been there, done that myself.