Group page urls naming convention


Just wanted to report a bug that I noticed, though not sure I can give you enough detail to determine why it happened.
I've noticed that when I migrated pages, one of the group pages urls appear to be using an id number (ex. 61ab8144-4601-42ec-98b6-ea2f64f27e20) .
When I try to edit the page details (such as the url) it tells me that "You are trying to access an item that no longer exists. The most probable reason is that it has been deleted by another user.", which is not the case, as the item is still there if I go back to pages.
I created a replacement page. When I tried to delete this page, it told me that workflow would not allow it, but deleted anyway.