TLDR, you need to make your variables unique to the page.
Basically what you are doing is you are rewriting the $session:ApplicationRequestGUID each time you open a new tab. This is because the $Session: scope is available between runspaces and is tied to your session with the dashboard. So you need to make that page “unique” in some way. You can pass a variable to the page to give it an assigned and unique value. That way you can create an entry in the hashtable to contain your variables.