Well I hate to say it, but at this point I’m at a loss. You indicated there was no continuity from jack set to jack set using an ohm meter, you could check that same thing from jack set to patchbay chassis. If there is no continuity it shouldn’t matter if the patchbays are touching each other or not.
You can try the other things I suggested in my post before my last as troubleshooting steps and report back, but I think you have issues going on that can’t be addressed without either being there in person to help, or you patiently following suggestions and posting responses with explicit detail. It takes a lot of work for helper and helpee to work through complex issues like this over a public forum. Like, I suspect the solution is relatively simple, but to get to it is likely complex in terms of sorting things out. You probably have more than one issue to resolve. I’m thinking if I was there there would be at least one thing where I’d go “oh, no, no. You need to [get rid of that/not use those/connect it this way]” that I might see pretty quickly, but you don’t know what’s important to share and I can’t know everything to ask you to share, so I’m looking at your problem through a peephole.
Anybody else have any ideas?
Like the first thing I’d do if I was there is verify continuity of jacks to jacks and jacks to chassis, verify serviceable condition of cables, and then start measuring chassis to chassis for stray/differential voltage…start looking at how signal ground relates to chassis ground for each device. But I can’t do all that from here.