Bypassing the Webtop to directly access a Portal Access resource via URI

Are you basically trying to always force a redirect when the host is myproductionAPMPolicy.com and uri is /mydefineduri?

One thing to note is that the ACCESS_POLICY_COMPLETED event is only executed at the end of the access policy, which happens once during a session. This would explain why you only see the redirect initially and not on any subsequent requests.

If you want to always check for that pre-defined uri (and/or host), you can also use the HTTP_REQUEST event. Something like this:

when HTTP_REQUEST {
    switch -glob [string tolower "[HTTP::host][HTTP::uri]"] {
        "myproductionapmpolicy.com/mydefineduri*" {
            HTTP::respond 302 Location "/f5-w-687474703a2f2f31302e312e332e36$$"
             You could use this instead too: HTTP::redirect "/f5-w-687474703a2f2f31302e312e332e36$$"

             If you have other iRules on this VIP the use HTTP::respond or HTTP::redirect, you may need a couple additional commands to mitigate a multiple redirects error.
            return
        }
    }
}

If you only want to perform the redirect after a session has been successfully completed, you might add an conditional before the switch to check for that. Something like this:

if {[ACCESS::policy result] -eq 'allow'} {
     Processing code here
}

Hope this helps.