Deleted pages still shown in the nav menu

Thank you for your answer. You’re definitly wright, this is linked with the sub-objects of these “ghost” pages.
How can I delete the sub admin page “Administration de la page” (WebPreferences)? There is no delete button in this page, and it is not listed in the page index (Main/AllDocs) section…
I have admin rights; I think something went wrong during the renaming process (option for sub-objects was checked).
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