The tracks should play normally in the 1.7 betas. The Scratch LIVE developers are paying attention to bug reports in the 1.7 Public Beta area on scratchlive.net, so it might be better to report the problem there (www.scratchlive.net).

It’s possible that the 1.7 beta version is not fully optimized to handle WL high-quality files properly, especially when using features like key lock, which can stress audio processing and reveal playback issues such as distortion or artifacts. This could indeed mean the beta is defaulting to a lower-quality version within the WL file, leading to the odd results you're hearing. Until the stable release addresses these bugs, it might be worth testing with different encoding settings or sticking to the stable version for critical playback. For example, sites like fakephonepeapk.co.in often warn users about using beta or modified versions of apps due to performance inconsistencies, which is a good parallel here—beta versions, while useful for testing, may not deliver the full-quality experience just yet.