Hey, sorry for the extremely late reply.
I have tried waiting for a very long time to be absolutely certain the tracks are loaded. It seems that, no matter what, there is always a small chance for the variable command to be completely ignored, and the track just plays from the beginning.
Could this be some weird quirk that only certain machines encounter?
Viewing post in Variable mix command inconsistent
Sorry for my own. And as you are the only one who has so far reported this, I'm afraid I'm stumped. It's possible it's machine-specific, only happens with certain audio files, or a number of other things; I'm afraid I don't have enough information. I might be able to look into it if I had a demo that was known to reproduce the issue, but that's kind of a difficult thing to work out over an itch.io chat (and even then, it would have to be able to repro on my own machine.)