Are you an Apple engineer, are you representing Apple with your post? Apparently you are questioning what happened, and your tone is exceedlingly patronizing and *arrogant* of you.
I will make it very clear again:
Approximately at 17:15 Pacific Time, I unlocked my phone using FaceID, this was working with iOS 16.5.1
I then did a backup of my phone to my macbook pro computer.
I then had it do a download and install 16.5.1
At iPhone reboot FaceID declared it could not work.
I called an actual Apple employee at 17:50, who asked me to run first reboot phone. That reboot did *NOT* fix the issue. She then had me run a diagnostic, which she accessed. There was no obvious issue she could see with the hardware based on the remote diagnostics she ran.
On the phone she even suggested that the Apple personnel at the store could downgrade my iOS back to 16.5.
Sounds like if she was offering that as a possible solution that indeed there could be an issue with 16.5.1.
I am posting here so that Apple analytics will see that other people are having the issue. And that others can also see that there might not *actually* be anything wrong with their phone.
Your patronizing post does *nothing* to contribute to the discussion.
Not all bugs are 100% penetrating, some can be subtle bugs. Just as side effects of drugs can be rare, software bugs can *also* be rare.