Well, a better word might be random, and not intermittent. Random, like twice in eight months.

This weekend I cleaned and tightened grounds and connections I could find. The cable clamps on the main battery posts weren't as tight as I would have expected, so I wire brushed to get them all shiny again and re-tightened. There was a bit of corrosion under each of the ground strap terminals I could find and I wire brushed those too. No signs of overheating or arcing around the starter and solenoid areas. I did clean and add a little dielectric grease to the small green wire and terminal that feeds the solenoid, and cleaned and tightened all of the big wire terminals at the starter.

Btw, I disconnected the battery before starting this work.