Cloned site, issue with editing pages


I have not experienced this before, so perhaps some guidance on resolution, or has any one else come across this.

I have successfully cloned a site, but when I go to edit the home page, the editor accepts the change, I hit update - instead of returning to the editor showing the changed text (the normal WP behaviour), it jumps out to 'all pages' and the change is not saved.

Any ideas?

p.s. another cloned site on the same multisite on teh same day doesn't have this issue