My car battery light is on

I have a 2010 Toyota Corolla S. Today, after driving around for 15 minutes, when I parked, my battery light came on. I took it to Autozone. After checking my battery and the changing system they said, everything seems ok. Nothing pop up in their machine. I was wondering what could cause this problem. I replace my battery in December 2019. And I replace my alternator 2 weeks ago.

N.B:

The first time I saw that the battery light came on, I turn off my
engine for 5 minutes and then start again, the battery sign was off.
After running the engine for 3/4 minutes, it came back on.

While I start the car for driving to AutoZone, the battery light was
off. Again after 4/5 minutes, It came on while I was driving. My
battery sign was still on, while the guy from AutoZone was checking
both the battery & the changing system. Then I turn off and on my
engine, that sign went off again.

Any comments, what might cause the problem?