Can't save page if parent was renamed

One of our developer experience issue that I was easily able to reproduce. If a page is being edited and parent page has been renamed, the page that is being edited can not be saved at all. Message "The parent page specified does not exist. It may have been renamed or removed since you started editing." is displayed, I believe this kind of functionality is a bug since WiKi editing is a collaborative process, alternatively renaming parents should not function when any child is being edited in order not to loose a lot of work.

Thank you.