irule not working as expected

HTTP::host is only the host, it doesn't include the URI.

host: cmsint-qa.abc.com path: /public/header.html uri: /public/header.html?SiteId=GCR

you'll want to split the conditions up so they'll match. You can add the host condition in there as well, but without it, something like this should work:

when HTTP_REQUEST {
 if { [HTTP::uri] equals "/public/header.html?SiteId=GCR"} {
   HTTP::redirect "https://gcr-qa.abc.com/public/header.html[HTTP::uri]"
  }
}