It's just weird. It's actually the WR● line coming from pin 4 of UH7 to pin 2 of the SWIM... the issue is that my multimeter gives close to 0 ohms... Yet it just doesn't want to work without a direct lead between the two pins, or the scope between any of the above pins and ground...

Grounding on UH7 is okay, pretty sure I checked that as well.

Such a shame. i really hope to just get around the final issue, without having to resort to the spaghetti-wire-method.