I MAY have a fix. This has been happening to us as well for 2+ months now
,I have spent hours on the home with Apple on our family shared account as we all were receiving the notifications and nothing has helped until now and here is what seems to be working for us. First off, remove apple AirPods from your Apple ID account completely. Then restore the AirPods completely as to a new condition by opening the cover and holding down the back pair button for 15 sec or more until light on the front pulsates in white light. Then, and this is very important! Go away from your home or business or school WIFI! You need to be on cell signal only, Go a few blocks away and then pair the AirPods to original owner ONLY, …… Since doing these steps, we are not getting the notifications that unknown AirPods are following you notifications anymore, I hope this helps, please let me know.