New fresh site with WordPress 3.8.3.
I did a straight wordpress import from the tools menu with a sample content file from my theme. Worked perfectly. Then I thought maybe I forgot to check the box to download attached media, so I ran the import again. As expected it told me that all of the posts and pages already existed so it did not import them again, BUT when I went to the site all of the menu items had been duplicated at all levels. I went to Appearance/Menus and sure enough every section had a twin.
I believe this has not happened before and should not?
It was not one full menu then another by the way, it was like this Top menu item1 and all of its sub menus, the Top menu item1 again with sub menus, Top menu item2 and all of its sub menus, the Top menu item2 again with sub menus and so on