Hey Big, you should read your complaints from where I'm sitting. Simply weird is an understatement. So, I'm going to add my wrinkle to it. It's obvious I'm not familiar with the product, meaning, is this a single ground wire, or is this, 'all grounds lead to one 'junction' point?
Notice all components cycle thru their jobber, i.e., coil, ehc, crank sensor. Mode LED's are not in CEL where lights are blinking, right? Clean LED readout is the assumption. So the weird think goes something like this... IF... this is like some wire harness grounds that have J-points, pull back the coping some and see if the bunched wires are cooked/cooking almost/to wrinkled plastic that covers the copper wiring.
Or... remove said ground wire or the J-point's eye ring, scrape new metal from how old is this bike? So ground integrity 'sometimes' need addressing due to electrolysis, 'especially [goes green is the] copper' eyes, wire, wire ends, pins, female connector ends, etc.
Last dead end before throwing parts at it.
Edit: Age is my connector pins goes green. So a random check is to pull said connectors apart, start with the crank sensor, look down into the pins and look for green electrolysis. If so, dip the whole connector end in vinegar, spoon a tea size amount of baking soda, and wait for the bubble to subside. Rinse with water, blow/air dry and reconnect. Test ride to another dead end road.