Thanks, Alex T⚜️! It seems like people still experienced strange behavior even after setting up the cron job correctly. For example, after I adjusted my cron job to run every minute, I clicked on upgrade, and the site still didn't upgrade after several minutes. Although I could see certain files like the splash page, did update. I had to click on upgrade one more time, then finally, everything updated.
By the way, the log showed that the upgrade was successful the first time. Even though it wasn't.
It's hard to say exactly what happened. Just sharing my experience.