Need help debugging an iRule to route to a specific pool memeber based on source ip

I just tested this on 11.3, so something else must be going on. Can you, as a test, simply try this:

when CLIENT_ACCEPTED {
    pool local-pool member 10.70.0.1 80
}

**changing pool name, member IP and port to reflect your local environment. Does this work? For all pool members?