[FWB]

Dan, i'm sure you have the problem licked.
just an observation from the pic of "the fix" you posted.

the eyelets seem to bottom out on the black, what i call "insulator"
giving a false sense of tight. as the wire cycles hot and cold it may shrink expand, get hard or all of the above, and may slowly be loose by itself.
i would place a washer on the alt stud first then attach the eyelets on the stud, when you then tighten the nut it will firmly bottom on metal and not catch the black insulator. i had to do this on both my powermaster starter and my one wire alternator