I created this video
to demonstrate what's going on. Essentially, we have two environments that are hosted on different servers. The one we host is using Umbraco and the other one is hosted with a third-party. The third-party uses a mask so that certain web-page requests are routed to our site. A problem arises however when users try to move back from our site to the other site -- I think it has something to do with caching, session state, or cookies. Any help or advice would be greatly appreciated. Thanks in advance!