FYI I had the same issue with that on my 2015. I called Kawasaki and created a case number and then took it to a dealer. They had a kawi tech come out, then the kawi rep approved it and they are fixing it with Kawasaki good willing the repair. They apparently used the wrong lock tite on some of the bevel ring gear nuts. Dealer said Kawasaki stands behind their stuff. This is a slow process though. It’s been over two months and I don’t have my machine e back yet. Apparently all the parts are back ordered because of covid bullshit. This a pretty involved repair as you need to remove the engine and split the case to get to this but. The good news is that there is a clip behind the nut so it won’t get any worse than it is now.
Actually wasn't too bad of a job and its now done thanks to that service manual so I really appreciate you linking that to me. The engine is a little bit daunting looking with all the timing chains and guides but if you go through the manual slowly it really isn't difficult. I made sure the nut had new red loctite on it and it was tightened with a rattle gun. It was very difficult to hold it in place and torque it. I actually really wanted to just weld a tack onto the nut/thread but didn't end up doing that in the end. Noise has completely gone away obviously!