Battery voltage drops to 5V with negative connected on a Ford Edge

So now it has fixed itself?
Makes me think PCM and it got reset when you unplugged....not that I can say I know how it works.
I guess it seems to be resolved for the time being?? That’s kinda what has been bugging us, because the car will start fine for days on end, and then one morning it’ll be dead.

So far, the voltage readings seem fine, so we will see what happens the next couple of days.