DrTumolo's picture shows that communication cable was repaired before
also very close to the hub you can see cut on shield of comm cable.
Cabling inside EPLUS motor is rock solid , nothing to look for. Electronics are another thing.
I suspect he didn't check comm cable for continuity properly, I guess continuity was intermittent
when you check for continuity you must wiggle comm cable around .
disc brakes are culprit pretty often