Well, I just replaced all the both the BD139s and the BC550Cs on the left side of the board.
Good news: I'm now able to properly set the voltage across R10 on both sides and currently have it at 230mV.
Bad news: Relay doesn't click at all now. (Which weirds me out because it was clicking even when I had the BD139 backwards)
I swapped out the opamp because I had an extra TL081 around, but the change yielded no effect. The diodes also check out.
Should I raise the voltage on both to produce a higher idle current? Could the e12 transistors be the culprits?
(replaced the e12 transistors and still no click)
Again, thanks for the help.
I should also note that I was was only able to get the correct voltage across R10L after changing out the BC550Cs, which I did after changing out the BD139s did not work.
Please measure the voltages on all the pins of both channel opamps. Let's see what the amp thinks it's doing.