Buzzing sound every day at 3:00pm

I have a very strange issue to report. My DreameHome L10s Plus makes a buzzing sound (like a phone on vibrate) each afternoon at precisely 3:00pm (told you it was strange!)

It took me weeks to track down the source of the noise, but I finally figured out that’s where it comes from. It buzzes twice (about 2 seconds per buzz) and that’s it until the next day at 3:00.

Does anyone have ANY idea what might be causing it?

Very strange! Anything scheduled for that time? Anything scheduled at all for 3pm?