Multiple Secure and HttpOnly attributes seen for cookie

Try using this iRule. It will not try to set secure or httponly if it is already set. What you are doing to manually changing the cookie payload without inspecting what is already there.

when HTTP_RESPONSE {
    foreach mycookie [HTTP::cookie names] {
        HTTP::cookie secure $mycookie enable
        HTTP::cookie httponly $mycookie enable
    }
}

https://devcentral.f5.com/wiki/iRules.HTTP__cookie.ashx