Not able to set response when using HTTP::Retry

I am trying to set up a simple Virtual Server in BigIP LTM that takes an HTTP request and sends it to all members in the pool assigned to it. My understanding is that HTTP:retry is, more or less, the only way to do so. I have written the following iRule

when RULE_INIT {
     Log debug locally to /var/log/ltm? 1=yes, 0=no
    set static::debug 1
}

when HTTP_REQUEST {
   log local0. "Entering HTTP Request"
    if { [HTTP::method] eq "GET"}{
        set request_headers [HTTP::request]
        if { $static::debug }{
            log local0. "Saving HTTP request headers: $request_headers"
        }
    }
}

when HTTP_RESPONSE {
    set response "Node request status"
    set curr_node_ip [LB::server addr]
    set curr_node_port [LB::server port]
    set node_status [HTTP::status]
    append response "$curr_node_ip:$curr_node_port$node_status"
    foreach member_node [active_members -list [LB::server pool]] {
        scan $member_node {%[^ ] %d} node_ip node_port
        if { $node_ip == $curr_node_ip and $node_port == $curr_node_port }{
            if { $static::debug }{
                log local0. "Skipping already collected data for $node_ip:$node_port"
            }
        } else {
            if { $static::debug }{
                log local0. "Sending request to $node_ip:$node_port"
            }
            pool [LB::server pool] member $node_ip $node_port
            HTTP::retry request_headers
            set node_status [HTTP::status]
            log local0. "$node_ip:$node_port sent answer $node_status"
            append response "$node_ip:$node_port$node_status"
        }
    }

    append response "" 
    log local0. "$response"
    HTTP::respond 200 content $response "Content-Type" "text/html" 
}

The problem is that I keep getting the following error when I run it

Illegal argument. Can't execute in the current context. (line 1)     invoked from within "HTTP::respond 200 content $response "Content-Type" "text/html""

Not having the HTTP:Retry call gets rid of the error but ofc breaks the whole point of the rule. Not having the HTTP::respond seems to allow the rule to run with retry in place however the client connection hangs and gets no response

I am using BigIP 10.0.10.4

Most of my research shows that people have been doing the same thing and able to use HTTP::retry together with HTTP::respond in that way however I cannot understand why it does not work here.

Am I missing something?