Yeah I think I can kind of see...
So, on the M BUSS PCB (the long connector board across the bottom of the mixer channel cards), both pins 7 & 8 of P909 are audio grounds. They are redundant, but it is important that both are viable. The “green strip” is called a trace. It is not actually green, that’s just a protective coating over the trace, and you can gently scrape that coating off to reveal the bare copper trace. I asked if you were handy with a soldering iron. You’ll need to be to repair it. What you need to do for a broken trace is remove the green varnish coating from the trace on either side of the break, then tin the bare copper trace with solder, and then take a short piece of bare tinned stranded or solid core wire and place that across the break like a bridge, and then solder that all in. And any pins that have been dislodged need to be straightened and put back into proper place and then resoldered.
Because you have pins that clearly have been abused/traumatized that tells me somebody at some point in your 388’s history was not appropriately careful when removing/reinstalling the M BUSS PCB. These thin narrow boards made from phenolic resin (rather than more durable glass fiber) that have lots of relatively high insertion/extraction force connectors MUST be handled VERY carefully when removing/reinstalling. They are fragile. Hammer mechanic approaches do not work here. Somebody went all hammer mechanic on your M BUSS PCB. So, if it was me, knowing this, I would execute the repairs to what I know is damaged and then furthermore I would resolder every single solder joint on the board. Furthermore, as I suggested earlier, for your AUX buss issue I would also inspect the solder joints on the MONITOR PCB. And don’t assume if it looks good to the naked eye it’s okay. You often can’t see cold solder joint or cracked joints without good light and a magnifying glass, and even then it can be missed, so that’s why, if I’m having trouble like you are having and my tracing the issue leads to potential solder joint issues I just reflow the applicable joints even if it only ends up being preventative.