I don't know. Sometimes electricity is a black art.
But the over voltage could have degraded some of the components in the box and it failed when you crank the car.
We have an old school local shop, that test our starters and alternators for free. You can test it yourself with a meter. Test the battery before you crank the car and after. You should see an increase of 1 to 2 volts. If you have more than 14 volt then remove the alternator and have it checked.
Remember each NASCAR race car has two MSD boxes!
Heat, vibration and over voltage, (currant spikes) will kill electronic components.
Dwight