I have the problem that it happens that I have a page and cannot change the layout and so not the sidebar. If I make e new page and copy the content from the page I could not change the layout then I can. But..then the slug will add a number behind the slug-name. Even when there is no page or post with the same name.
Beside that I’m very happy and thankful with the theme!
It is very hard to tell anything on this problem is so generalist. I would like more details. ( Link / Screenshot / Back End Screenshot for page / Settings > Reading Screenshot / Theme Options Screenshot )
About Duplicate Pages:
It is possible to create two pages with the same name but the link can not be identical.