Apple iPhone Connectivity Test?

I’m seeing a lot of entries in my proxy log from an iPhone on my network connecting to the URL:

If you go to that link, the message “AV is here!” displays.
I’m getting these entries about 25-30 times a minute. Has anybody seen these and know how to stop them? It’s only started about 5 days ago. Is it possibly related to an IOS upgrade?
I’ve seen posts where it says these are connection checks and don’t think they are harmful, just annoying.

I’m assuming no…