Auto mode shuts off as soon as you manually control the fan, right?

If that's the case, I rarely, if ever, use AUTO mode. I'm usually controlling the fan myself.

Also, yes, I am able to turn the A/C back on.

This has happened to me only maybe 3/4 times since I owned the car, and I usually use the A/C...so this will be hard to reproduce and test.

Yesterday was the only time that the heat actually turned on. The other times the A/C just shut off.