I mentioned in my post about music library managers that Apple Music doubles the lengths of my tracks in the metadata, but plays the tracks at their normal length. I’ve discovered this is because I’m converting lossless files to, specifically, variable bit rate MP3s; for some reason, there’s something wrong or incorrect in the header metadata that is only read by or affects Apple Music. You can fix this with something like foobar2000, though foobar2000 doesn’t have a bulk repair option (at least as far as I could tell). Or use, like, literally any other music player.