I had an original battery cable with the fused positive starter eyelet and the small starter outlet surrounded by the plastic/rubber connector that failed one time. Turned out, that junction holding both wires just at the starter was bad. The large eyelet would not always have a connection. occasionally it worked, occasionally it didn't.
One day I just got so frustrated, I replaced the positive cable and never had a problem again. I could hook an ohm meter to both ends of the big wire, and if you moved the cable just right, it lost continuity, but most of the time it was good. Drove me crazy chasing that one.

Kind of reminded my of the no start coil wire terminal issue. There were times the truck simply would not start. We replaced everything on the ignition system several times, it would work for a month or so, then we started the entire process again.
One day a mechanic friend told me to give all the truck wiring on the ignition system "The tug test" Simply put, while each wire is connected to whatever it connects to, you grab the wire and give it a good tug. If it pulls apart, or fails, it was defective before and was probably at least part of your intermittent problem. In his words, you can't tug apart a good 22 gauge wire and it connector with your bare hand, you sure can't tug apart a 1416 or a 14 gauge wire and its connector apart. And if the terminal is secured with a nut on a threaded post, and it failed the tug test, it too was already defective. The threaded post, the material holding the threaded post, or the wire terminal should not pull loose if the connection is good or the housing is not cracked. The tug test is not a brutal assault, but a hook your fingers around the wire, tug on it, and see if it pulls free. I've found so many bad wire connectors with the simple pull test.
on the truck with the ignition problem, the tug test broke the switch source terminal on the coil positive, turned out, there was 2 or 3 strands of wire (16 gauge) still making contact inside that enclosed terminal end. The tug test broke those last 2 or 3 strands of wire. Crimped on a new terminal and never had a problem with that truck again.