Add Ip member pool in my header browser

I found the reason for the failure of the rule STREAM: expression.

I have two members in my pool test when both are active, it dysfunctional.

If I remove a member, it works.

Have you any idea?

 
 when HTTP_RESPONSE { 
  
     Need to explicitly disable the stream profile by default so it doesn't stay  
       enabled for subsequent HTTP requests on the same TCP connection. 
    STREAM::disable 
  
     Apply stream profile against text responses from the application 
    if { [HTTP::header value Content-Type] contains "text" }{ 
  
       switch [IP::server_addr] { 
         "10.x.x.156" { set nvip "mnr04 nvir0156" } 
         "10.x.x.157" { set nvip "mnr04 nvir0157" } 
         default         { set nvip [IP::server_addr]} 
        } 
  
        Replace  with 1.1.1.1 where 1.1.1.1 is the server IP adddress    
       STREAM::expression "@<\[Tt\]\[Ii\]\[Tt\]\[Ll\]\[Ee\]>@$nvip - @" 
  
        Enable the stream profile 
       STREAM::enable 
    } 
 }