iRule not sending traffic to the specified pool

Experts, I have a simple iRule to direct traffic on a particular vip to a pool. For some reason we still see a little traffic on servers outside the pool. Just wanted to make sure the iRule is fine to begin with. Ironically the /l/ and /r/ conditions are obeyed but not the /landing/.

when HTTP_REQUEST {
   if { [string tolower [HTTP::host]] equals "www.mycompany.com" && ([string tolower [HTTP::uri]] starts_with "/r/" or [string tolower [HTTP::uri]] starts_with "/l/" or [string tolower [HTTP::uri]] starts_with "/landing/") } {
      pool www.mycompany.com_landing_80_pool
   }
}