I do not have 100% protected restricted content

I am planning to launch my website sometime this month and I have been going back and fourth to double check that all of the restricted content is restricted.

The protected page contains the portfolio and the portfolio appears no where else in the website making it exclusive to the members only. However, opening up a new page in a different web browser and simply copying and pasting that project's url allows anyone access to it.

I have included the project shortcode in the negative rule set for visitor users but still no luck. Is there any suggestions as to how I can overcome this problem?

thanks,
Nathan