U.S. test of national alerts on Oct. 4 at 2:20pm EDT (1820 UTC)

Wed Oct 4 18:42:27 UTC 2023

On Wed, 4 Oct 2023, Ryan A. Krenzischek wrote:
> I've only gotten the alert now ...9 times.

Unless you keep turning your phone off, alerts have a serial number. 
Phones check the serial number for recently received alerts.

Or so Android and iOS developers claim.  If you are getting duplicate 
alerts, their advice is the standard I.T. mantra -- turn you phone off and 
on again.