Need an extra pair of eyes on my irule please- Block access to specific uri path

I'm attempting to prevent users from accessing a folder/page externally and it appears that this blocks for most, however the app team says that they can still get to it sometimes. I cannot reproduce it, was hoping I could get an extra pair of eyes on it as I cannot reproduce it with IE or FireFox but they sent me a screenshot with the page loaded with the full url/uri in the path so I might be missing something.

I have asked how, and am awaiting a response on how they are actually reproducing and getting to it. It sounds like they are using Firefox and some how still able to get to it.

Thanks all!

Code:

set lower_uri [string tolower [HTTP::uri]]

 Define the variables
set uri1 "/uricodeunwantedbyexternal/"
set srvpool "www.xyz.com"
set redirect_path https://www.xyz.com

if { ($lower_uri starts_with $uri1) } { 
       log local0. "blocked $uri1 contains; redirecting traffic [HTTP::uri]"
      HTTP::redirect $redirect_path
    Else, pass request
} else {
       log local0. External user and uri does not match allowed uri's[HTTP::uri]
      pool $srvpool

   }
}