iPhone 13 Pro Max Unknown alarm going off even after power cycle and all apps closed?

[jpiszcz]

Have been using iPhones for > 10 years and never had this happen, using latest iOS 15.3.1 as of this posting.
1) Does anyone know what this sound is from or what it is supposed to be indicating?
2) All applications are closed, it even started up again after a power cycle..?
3) After a third reboot, it has stopped..

I was able to capture the alarm noise via a screen recording, any thoughts on what this is?

 

[now i see it]

Maybe Emergency or Amber or Public Alert?
Scroll to the bottom of the Notifications settings and see if they’re enabled. If so — maybe turn them off if it’s bothering you.

 

[Nathan576]

No clue but that’s hilarious ?