Good day @jan_stolzenberg , Your G4 makes very strange sounds, I have never encountered anything like this. I think you need to contact aqara support or wait for a comment here from the product manager. Here is the email of aqara technical support. support@aqara.com
Mine has started doing this exact same thing a couple of weeks ago. I originally installed it about 17 months ago and it worked flawlessly up until it started making this noise.