I Cant clone a cloned site?

Hi, for some reason i can clone the main multisite and 1 other cloned version but when i try to clone a clone the url should be for example clone.mywebsite.com but instead its not available and the url remains as mywebsite.com without the clone.

This is a new thing so i’m thinking that it may be a setting that ive configured incorrectly?

i want to clone the main site and then strip it back so i can then use the simple version to clone moving forward, but unfortunately, the above issue is a roadblock!

Thanks, glen.