Cookie Expiration modification not making it to the browser

Hey guys we have a simple irule that is suppose to modify a cookie that we have in the browser. The cookie looks to get modified from the LTM side but that cookie change never makes it back to the browser.

Ideally we want the cookie to expire at end of session (when browser is closed)

connection goes through a VIP that has SSL offloading

Here is an example of the irule

when HTTP_RESPONSE {

   if {$::my_host_header eq "subdomain.domain.com"} {

       set cookies [HTTP::cookie names]

       foreach aCookie $cookies {

           if {$aCookie eq "Portal"} {

               log local0. "[IP::client_addr]:[TCP::client_port]: Before Set-Cookie: [HTTP::header values Set-Cookie]"

               #HTTP::cookie sanitize $aCookie path|secure|samesite|priority|maxage|expires

               HTTP::cookie expires $aCookie 1 absolute

               #HTTP::cookie remove $aCookie

               #HTTP::cookie attribute $aCookie value "expires" "Thu, 01-Jan-1970 00:00:00 GMT"

               #HTTP::cookie maxage $aCookie 01-Jan-1970

               log local0. "[IP::client_addr]:[TCP::client_port]: After Set-Cookie: [HTTP::header values Set-Cookie]"

           }elseif {$aCookie eq "Portal2"} {

               log local0. "[IP::client_addr]:[TCP::client_port]: Portal 2 Found: [HTTP::header values Set-Cookie]"

           }

       }

   }

}

Here is the LTM Logs

Rule /Common/DS-Cookie-iRule <HTTP_RESPONSE>: 10.10.45.xx:51571: After Set-Cookie: {Portal=; expires=Thu, 01-Jan-1970 00:00:01 GMT; path=/; samesite=lax} {Portal=CfDJ8DxA

I attached the browser, it isnt edited =(