Auth_Status and Persist

I think the bigger issues are this:

1. When the server sends back a 401, presumably to request authentication, you're immediate changing that to a 302 redirect. I don't suspect you're getting prompted for authentication??

2. If you let the 401 through to the client (don't do the redirect), then you should only need to check for the existence of the "PD-S-SESSION-ID-PROD2" cookie (sent in the 401) on each future request to send traffic back to poolK. So perhaps something like this:

when HTTP_REQUEST {
    if { ( [string tolower [HTTP::uri]] starts_with "/nad" ) or ( [HTTP::cookie exists PD-S-SESSION-ID-PROD2] ) } {
        pool poolK
    }
}

You would also want to enable a OneConnect profile and (simple) cookie persistence.