The Membership plugin is presenting a serious flaw. How to solve it?

I noticed a flaw in the protection of the Membership plugin when typed urls protected page.

For example: The page http://clubedodesign.com/premium, is protected from visitors, and is only visible to members.
However, if you add a simple "/" (slash) at the end of the url, you have access to all content of the page: http://clubedodesign.com/premium/

You can access the examples above and see for himself. In the first case you will come across my page protection. In the second, will access everything that should be protected, using only a "/".

I would like this problem to be corrected, because the urls of the wordpress have "/" by default, and this does not allow me to disclose my links for members safely.

I await your support.

Regards

Ps. Sorry for bad english ... I'm using a translator.