I'd be interested to know whether, if you reboot the watch by long-pressing the button and keep it pressed so you enter the recovery menu, if you let the screen go off and then press the button to unlock it whether you get a buzz then?
If not, it'll be a software issue - might be an idea to backup the watch using the app loader, then do a factory reset and slowly reinstall apps and see when/if it starts happening
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Is the firmware and all the software up to date?
I'd be interested to know whether, if you reboot the watch by long-pressing the button and keep it pressed so you enter the recovery menu, if you let the screen go off and then press the button to unlock it whether you get a buzz then?
If not, it'll be a software issue - might be an idea to backup the watch using the app loader, then do a factory reset and slowly reinstall apps and see when/if it starts happening