It’s not just you. I get multiples on all my pings and I know some posters who say it happens to them on smart phones. Not that smart I guess. Someone had about 12 multiples post a little while back.
Best way to prevent it is to count 2 seconds after you hit POST for your PING and then close the window. Then check it out to make sure you have only one PING posted. Works for me only I didn’t think I would need it for a shorter PING list.