Blew a capacitor on a customer build once, now I sniff every PSU first.

Did you actually go back and finish any of those 9 shows later, or just write them all off?

Why would a smart timer reset at the same time every morning though? That sounds less like a bad ground and more like a schedule or power issue to me. Ground wires don't usually care what time it is, they're either making contact or they're not. If it truly was the ground, you'd expect random resets all day, not a neat 7 AM pattern. Not saying you're wrong about what you found, but the corroded wire might have been a coincidence you fixed along the way. Four visits and 11 hours for a ground wire sounds like the real problem was never pinned down and it just stopped acting up.