one rewrite url works and another does not.

try this for logging (irule from Lee with logging request not matching any of 2 conditions)

when HTTP_REQUEST { 
    if {[HTTP::host] equals "intfilings.abc.gov"} {
        if {[HTTP::uri] starts_with "/navigator_icm"} {
            log local0. "replacing host header with : server1.ct.gov on URI: [HTTP::uri]"
            HTTP::header replace Host "server1.ct.gov" 
        } elseif {[HTTP::uri] starts_with "/EFilingWeb"} {
            log local0. "replacing host header with : server2.ct.gov on URI: [HTTP::uri]"
            HTTP::header replace Host "server2.ct.gov"
        } else {
            log local0. "Unchanged host header on URI: [HTTP::uri]"
        }
    }
}