Nested pages below level 3 not indenting

The menu sync option is just what I was looking for! One small issue: I only get 3 levels of indentation for nested pages. When there is a fourth level the pages are listed below their parent, but at the same level of indentation.

What I expect to see is this…

One
   L Two
      L Three
         L Four
            L Five A
            L Five B

What I actually see is this…

One
   L Two
      L Three
         L Four
         L Five A
         L Five B

The expansion button on the “Four” line hides/shows the “Five” lines below, but not indented.

https://wordpress.org/plugins/wp-nested-pages/