I imported a stereo mp3 to pt 2021 and the track #1 switched from stereo to mono. Earlier, I noticed while working on a song that my main music track was mono, and i wasn't sure why. Now, as I was importing a stereo mp3 track, I noticed right before my eyes that track #1 switched to mono!!! Then of course when you switch it back, it says you can't change it because there's data in it.