If Bob's coil is on a hot shroud, I get what you're saying, @Sacto Mitch.
Is it, @Panhandle Bob? And what voltage is your coil at, engine running?
My coil sits on the trans right by the LONG trans bolt. It gets all the underhood heat, no tins in my Spyder separating hot and cold air to the engine. The hot cylinder air is ducted right under the coil by my home-made reverse sled tins.
Modern coil-on-plug setups have the coil right on top of the HOT cylinder head.
I'm not sure, but I don't think heat affects coils today like it used to back in the day.
I still am of a mind that instead of using cheap max-profit components in the points module, there would be a much lower failure rate.
Bob's problem could be as simple as a slightly intermittent connection. Not intermittent or bad enough to misfire, but electronics can be sensitive to resistance or quick open/closing current from an intermittent connection.
After two modules, I'd replace everything, because this is getting EXPENSIVE!