Ask HN: The interesting case of the endless DNS propagation

One day about a year ago, I've noticed that the site www.aqadvisor.com was offline. (I could see a page saying "this domain is for sale" or something to that effect).

I posted about that on an aquarium hobbyists forum and several users replied they could still access the site, although a few others could not.

So I decided to run a search with DNS propagation checker and it seemed that the A record was propagating so I though "oh they must have just changed their IP".

The problem is, after about a year... it seems it's still "propagating"?

https://www.whatsmydns.net/#A/www.aqadvisor.com

How come that different ISPs can't agree on the value of this A record?

The authoritative ns for this domain is bizprime2.com:

     host -t ns www.aqadvisor.com
    www.aqadvisor.com is an alias for aqadvisor.com.
    aqadvisor.com name server ns1.bizprime2.com.
    aqadvisor.com name server ns2.bizprime2.com.

and that name server, interestingly, returns the "wrong" IP, meaning that if you use that IP you will see the message "this domain is for sale", not the actual website. However both Google NS and Cloudflare are returning the "right" IP, i.e. the one that actually lets you access the website.

So what's going on here exactly?

This seems really peculiar and I'm curious :-)