alarm

Yours is the first comment, so no known issues. 

I would recommend that you submit a system diagnostic within 10 minutes of reproducing the issue, and call Sonos Support to discuss it. Do not factory reset any units. Also, don’t post the resulting diagnostic number here.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution, even if there is a conflict with the new version of iOS, which would be doubtful.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Also, note the alarm is stored on the Sonos system, not your iOS device which received the update. The alarm should continue to work even after your phone leaves the network. 
 

FWIW, my iPhone updated to 27.2 (no .1). It is a iPhone 16, but all the reports seem to report there isn’t a 27.2.1 yet as a regular release. Any chance your device is running a beta version? Sonos doesn’t support beta versions of OS, but I can’t see how that might affect the alarms…but that diagnostic might help Sonos see something I can’t.