Did some more experimenting. I forgot to mention it's the garage of an apartment building, so I need to go through my manager (just a couple days ago they agreed to let me charge for free as a favor while they're working on installing one I'll pay for, so I hate having to say anything!).
I did try plugging it into another outlet I found in the garage, and my car charged as expected in that outlet. The broken outlet does appear to charge other electronics and will still light up the Tesla charging adapter, but it definitely appears to be an issue with that outlet. This morning it was still doing the same thing, showing 0 out of 12 amps and 175-177 volts, but then later this morning, I tried it again, and the charging adaptor still lights up at first, but when plugged into the car, the car now says to check the AC equipment, the adapter started flashing Tesla, and the screen showed 0/0 amps and 2 volts. So it appears to definitely be something wrong with that outlet. It seems to have been working for about 2-3 hours by the time I was notified last night that it has stopped charging.
There appears to be no other electrical issue in the building, so I'm worried what my building manager might conclude if the only thing broken is the one that was charging my car!
Thanks all!