That would be SO annoying …
A post on the Sonos support forums explains what’s going on.According to John M, the company discovered a bug in its software that pertains to leap year handling. Unfortunately, they can’t fix it in time, so until the end of New Year’s Day, alarms will continue to have issues. For now, the recommendation is to disable existing alarms (info on how to set/change alarms is here), and John says there will be a fix included in a future update to keep this from happening again.
“I just changed the sonos system date to 2015 and the problem is solved. At least this morning.”
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