I'm not sure if this would help you on Restrict Content Pro but may help others.

I am running Profile Builder Basic but fooled around with Restrict Content Pro in the early research phases of site build out.

The solution for me was to create a NEW page with no copied over elements and rebuild it.

Background:

After going around in circles of staging website, disabling all plugins, and caching services, I still couldn't find what was causing it. My plan was to try and put people through the native Wordpress login/logout screen. However, after that plan failed as they were still experiencing the logged in cookie on that one page that as my culprit (/portal).

The plugin I was using was Profile Builder Basic. However, in my early development stages I was fooling around with Restrict Content Pro. My hypothesis is that something under the hood is misaligning or a leftover fragment from that plugin.

After logging out on the new /portal-2 page, and when I revisit the /portal page, it was identifying I was logged out and not sending me in a loop showing I'm logged in. :D