I've used a few in parallel without a problem. There is a limit in the totalamount you can have, I think 32 mono tracks. Once when I purged unused samples my audio track disappeared, but I have not seen that bug again and otherwiase the operation is glitch free,
Note that if you are recording directly into an audio track there will be a short silence inserted at the start. You can manually edit this away later if necessary. There is no punch in and punch out recording. There is no current way to 'split' or edit an audio track. You cannot copy, for example, bars 3 and 4 and easily place it at bars 5 and 7. I am not sure, but I think you cannot record a bar in the middle of the audio track, as the original will not play after your recording. You can think of the audio track as containing triggers on a bar, which play a long wav file. So on bar 1 you trigger a long wav file, and then on bar 32 you might trigger another, but if you record audio into bar 20 only, you get a new wav from 20 to 21, and there will be silence from 21 to 32 as the original wav does not resume...
Basically, audio tracks are ok if you want a long wav files which play from specific bars (like a verse wav, or a chorus wav) but you'll immediately run into limitations if you want to edit and do anything else with them, I just import the whole vocal stem from my computer and lay down beats alongside the audio track, and for that it works pretty well
