I wonder how sophisticated the ECM is? Can it store an RPM trace? If the belt literally snapped at WOT the rev limiter may not be able to prevent a serious over-rev?? Just spitballing.
I don't spend enough time on the KRX forum to give a number, but my guess would be people running them harder. A common complaint was the primary getting "notchy", and acting like it was stepping through the ratios, instead of smoothly shifting. I know that Steve guy has done hundreds of KRX...