Santa Fe XL Loses Power When Starting the Car

I've had this happen twice in the past month but haven't been able to reliably replicate the issue and was wondering if anyone has heard of something like this.

In both cases, I was able to open my car with the fob (so power's running) but when I hit the push button to start the car, my 2019 Santa Fe XL (Ultimate/FWD) starts to turn over but then the car dies. There's no power or, I can barely turn the steering wheel, the key fob gets to reaction, etc.

The first time it happened, I'd parked and turned off the car, ran into the post office and came out within 2 minutes. After sitting in the car for a couple of minutes, it appeared to reboot on its own with the power coming back on... but as soon as I hit the ignition button, I got the same power outage.

Thinking it might be the battery (though I replaced it maybe 21 months ago), I popped the hood and lifted the cover over the red terminal. Everything looked clean with no signs of corrosion or obvious loose connections. At about that point, however, the car rebooted again and this time I was able to successfully start it. I then closed up the hood and drove home.

I attempted to recreate the issue several times but had no luck. We ended up taking the Santa Fe on a short driving trip this past weekend and, sure enough, Sunday afternoon the same thing happened again. The time between my stopping & parking the car and attempting to restart it was closer to an hour this time but it was the same symptoms.

This time, however, I immediately opened the hood & lifted the cover, and as soon as I did that, I heard things start to click and move and my wife yelled out that the car was coming back to life. Sure enough, she started up right away and has been fine every since.

I need this to happen again to test my emerging theory but the fact that I lifted the cover on the battery terminal both times right before successfully restarting the car has me thinking that's where my issue's located... but as it's only happened twice, it could also just be a coincidence. Plus, I've never heard of a battery terminal cover having any effect in the power system. Still, this Santa Fe is the most "advanced" car I've owned so maybe I'm behind the times.

Still, if anyone has any thoughts on this, I'd welcome them. Thanks!