Depends how you do it. If you just want to run the audio through the effects, you don’t need to use one of the regular tracks. You can control the input volume on the Ext In page in the FX track and that’s it. Set your levels there, and run your instrument through the global effects settings.
However, running instruments through the regular tracks is a bit inconsistent for me too. I use it for guitar sometimes. I’ve gotten audio without triggers sometimes, other times absolute silence. It would be nice to not need the triggers at all if you select L or R waveforms.