Parenthese Octave no effect and loud hum at full

[SweetBerryWine]

I'm stuck with the Parentheses build and am getting a major volume drop when I engage the Octave pedal and in the final 20% of turning the Octave pot CW, it makes a loud oscillating hum. The distortion, boost, and diode switching all work as they should. The Octave pot even makes the loud hum at full CW when the Octave pedal isn't engaged.

I know it's been asked a lot and I've gone through the suggestions people mentioned here of confirming matching D1/D2 diodes (I had 1N5817s and just swapped for BAT41s) and reflowing and confirming all components are correct values. I'm going to dig into it further tomorrow with my multimeter but am still new to the troubleshooting and knowing what to look for from the readings and schematic. Any suggestions on what could be the issue or what to look for?

 

[Locrian99]

I would first just reflow solder joints if you havent yet.

Here is the octave part.

I would audio probe it and see where the noise is introduced

 

[Nostradoomus]

what did you use for Q1?