If your website is hosted in a shared server, the reverse IP address will point to the main domain of that server. Unless you have a dedicated server, the reverse IP address will not return the domain of your website.
Here’s an example:
$ host -t A sucuri.net.
sucuri.net has address 192.124.249.16
$ host -t A 192.124.249.16
domain name pointer cloudproxy10016.sucuri.net.
In the example above, we are querying the DNS A record from a specific domain name, the DNS A record contains the IP address that the domain is pointing to. Then, we reverse the IP address to attempt to recover the original domain name, but as you can see the operation returns “cloudproxy10016.sucuri.net” instead of “sucuri.net”.
This is what may be happening in your case and there’s nothing wrong with that.
Let me know if you need more information.