Clean-Transparent Guitar Pedal.

Hello! I'm having a strange issue with the audio output, and would appreciate any advice possible!

So everything seems to be working mostly fine. I have very nice audio coming through the Amp, except quietly in the background (maybe 1/5 of the volume of the clean audio) there's the same guitar signal but heavily distorted. I tried adjusting the variable resistor and it might have slightly changed how loud or quiet this faint distorted signal but it's still there. Isn't all the sound output generated at the PWM? How could some of my audio output be perfect and also some of it be distorted? Also the sustain is strange, when a note rings for very long it sort of gets cut out abruptly (is this related to the capacitors RC time?). Thanks in advance for any help!

Edit: The quieter signal sounds more like fuzz if that's useful. Also, I don't have an oscilloscope at my disposal. If I did troubleshooting this would be far easier.

Thanks for the reply! I actually just rebuilt the whole project and fiddled with RV1 a bit (opened it up a bit) and now the sound is clean and working fine.