I spent a long time trying to figure out how to fix this.
Even though sitemaps generated for goolge tells them the link is Directory/index.html
....they try to spider Directory/
This causes 404's and bad rank.

I thought the 'default index file' in config would take care of that but it doesn't seem to work that way with my install.

DirectoryIndex index.html index.php in the htaccess was not working for me either.

The way I fixed it was to put a custom 301 redirect in with relative paths, that is, ...no http://

Click the View/Edit 301 Urls and adjust it there.

Mine for example was

{Moved from URL}
faq-and-support/

{Moved to URL}
faq-and-support/index.html