I've not checked the wires in the harness for the EA. The car has an updated engine harness, but I don't know if that includes the EA. I'll check all of the wires coming to the EA.

Since this behavior is triggered by "relatively violent" suspension travel, I'm thinking there are wires somewhere coming into contact when they shouldn't.

Normal cruise is never effected - just things like over speed bumps, big dips in the road, rough or undulating pavement around 20mph or less, etc. Something's getting wiggled and is mis-behaving.

I'm not beyond rewiring the EA if that's what it comes to. Just checked the part at MB and it's $1760 list.