Unknown alarm sounds on iPhone after Apple Watch is taken off charger

I occasionally get an unknown / unidentified, alarm / ringing that sounds on my iphone after I take my watch off the charger and unlock it with my PIN. Apple Watch SE 3, watchOS 27.0.1 / iphone 13, iOS 27.0.1. This issue only started after I got my watch. I don't use alarms on my phone. My "alarms" app on my watch shows no alarms are set. Since virtually every response on the internet referred to the wake alarm associated with the sleep schedule in health, I add the following notes; a) I did not use the health app until I got my watch; b) I only use it to track items such as; steps, heart rate, respiration rate, and sleep length and quality; c) I set a sleep schedule to get a sleep score - I have not set a wake up alarm; d) this happens before I go to sleep (I charge it so I can wear it while sleeping). Thanks in advance for any comments.