Steps to Reproduce:

  • Create new page with '/node/%node/foo' path
  • Set menu type as 'Menu tab'
  • Add selection rule 'Logged in user has role "authenticated user"'
  • Save

When you go to '/node/%node' as anonymous user, you still see 'Foo' tab.
If you click on it - you will see 'The requested page "/node/%node/foo" could not be found.'