My first mopar "stranded" moment with the HEI setup

It happens, but it's rare.
It's possible that the module was sold as a Standard Motor Products part, but actually isn't also.

Been running the same module on my car for 4 years and thousands and thousands of miles without so much as a hiccup, but I use factory GM 8 pin modules.
One other thing is that 4 pin modules are prone to low voltage death, so you may very well have run across one of these shortfalls.
The 8 pin module is a lot more stable and less prone to voltage issue's, and this is one of the reasons we use them in our HEI Kits instead of the four pin.
(well that and the 8's are a much more reliable and visually cleaner connection setup.) which could have killed your 4 pin from low voltage with the blade connections.