Excellent photos. Thank you.
Now it sounds like your relay may be working properly after the microcontroller leads are thoroughly in the socket. Do you hear the relay click when the bypass switch is pressed?
Make sure that pins 15 and 16 are seated properly too because those are the pins that control the optocoupler LEDs.
It doesn’t matter how the socked is orientated as long as the IC in facing the correct way.
If the issue was with the jp2, which is the high frequency signal path, you would still hear the low signal path going through jp1, so i’m not sure that is the issue.
I noticed you have a lot of solder on most of the joints…double check all the solder joints, especially around U2 to make sure there are no shorts. I know you probably are doing this already, but make sure you use the insulation paper under the pots to ensure that nothing is shorted to the back of pots.
Let me know what you find.
-Brach