Hum sound from chime box

Connected G4 Aqara doorbell. Worked fine until today. I noticed some weird humming sound coming from chime box. It disappears if remove wiring from the doorbell (switch to battery mode). Read that it can be leaked voltage. And can be solved by installing resistor. I am concerned that this sound had appeared only now after few months of usage. Is it safe to use? Sound is not terrible - can live with it