Ok I've found the issue!
Cause of my issue: I batch assigned the registered_user role to a bunch of users on my website. But in doing so I also assigned the registered_user role to the default guest user.
This of course caused anyone who was not logged in to have the registered_user role and made them able to view pages they weren't supposed to.
Sorry for overlooking this issue before posting here and thanks again for your help everyone!
