R7 C5 Switch Not Working

[j1n6]

Hi There,

I have this strange behaviour with the switch at Row 7 Column 5 location.
The switch definitely works at R7C5. When only left side is connected to the USB, it responds to typing.
When both sides are connected via TRRS, and USB is connected to the right side board, R7C5 doesn't seem to register.

In short, the R7C5 stops working only when TRRS cable is plugged in..
I tested it happens to default firmware. Do you know what issue might be?

Thanks in advance.

[j1n6]

Found the problem - it was the left side short detector - I didn't put enough solder to make it through hole.