I can't disagree on this circuit not making sense, especially since I have two unknown components: the one marked G21 and a hybrid. I measured point-to-point several times, so a possibility exists I made an error in transition from measuring, to writing, to drawing the circuits, but I've checked everything several times. I made a small error on the schematic - the 100 ohm resistor is before pin 1 on the G21 - I've redrawn that section - and added the second circuit in question on the bottom. Attached is a picture of the board - I drew a red circle around G21 and two lines pointing to the vias that are connected. So I've pretty much have one pin that's correct because it's visible on the board (the 100 ohm resistor), and I am confident the two vias are connected making two pins correct.
I removed the G21 from a good channel and measured it - see attached for the updated list of measurements.
From what I can tell, the AD 823 on both Ch 2 and Ch 3 (the bad channels) was replaced by someone, and, it appears the G21 component too. My measurements led me to these two components, and, after looking at the soldering, it appears they were replaced by someone finding the same differences in measurements. I plan to replace both components in both channels, so I'm still interested in knowing what this G21 component is.
What I also noticed is the AD 823 in Ch 2 and Ch3 has a dark marking instead of a shiny silver one; and they are AD 823A instead of 823 (not sure if it's an issue, but I'll look later, just wanted to mention it). The interesting thing is the G21 in Ch 2 and Ch 3 have the sideways 32 suggesting they were replaced with the wrong component because Ch 1 and Ch4 have just a plan G21.
Attached is a picture of each G21 showing the 32 on two of them to avoid any doubt on what I'm referring to.