X-Forwarded-For - IRule

Hello, Im trying to implement a IRule to work with X-Forwarded-For HTTP headers, but it doesnt seems to be working correctly.

My IRule is the following:

if { [HTTP::header exists "X-Forwarded-For"] } { log local0. "X-Forward-IP: [HTTP::header values "X-Forwarded-For"] , Original X-Forward, Client IP: [IP::client_addr] "

                            set test [getfield [lindex  [HTTP::header values X-Forwarded-For]  0] "," 1]
                log local0. "X-Forward-IP only the first:  $test"

     it replaces in header e let only the first IP              
                            HTTP::header replace "X-Forwarded-For" $test
                            persist uie [HTTP::header X-Forwarded-For] 600

            } else {
                HTTP::header insert "X-Forwarded-For" [IP::client_addr]
            persist uie [HTTP::header X-Forwarded-For] 600

            log local0. "X-Forward-IP:  [HTTP::header values "X-Forwarded-For"] , Replaced by the client IP"
}

Logs collected in BIGIP shows:

: X-Forward-IP: 199.53.38.39 , Original X-Forward, Client IP: 192.168.121.150 Dec 16 09:42:55 cshgltm01 info tmm[14265]: Rule /Producao/irule_PROD_site_wwwroot : X-Forward-IP only the first: 199.53.38.39

But logs on Server shows: X-Forwarded-For: 192.168.121.150

I didnot get why it is occurring.