Irule for Cookie persistence on pool

HI all, I have written an Irule as follow:

Select different persistence methods by HTTP URI

when HTTP_REQUEST {

Check the requested URI switch -glob [HTTP::uri] { "/cares/" - "/fraud/" - "/submit/*" - "/exchange/" - "/webauth/" { Request was for an Sticky URI so select the pool and unset persistence persist cookie insert CSWEB-STICK pool CSWEB-STICK

  }
  default {
      Request was for an NON sticky URI so select the pool and persist with default persistance profile
     persist none
     pool CSWEB-NSTICK
  }

} }

The problem is that on the selection of the pool that should stick with a cookie persistence, it is not working. In the logs I see the following Mar 4 10:55:23 ASH1-PROD3900-01 info tmm[11443]: Rule /Common/Persistence-logger : Request from client: 172.21.81.144:57111 contains no persistence cookie on vip /Common/CSWEB-PERSISTENCE-TEST; request was assigned to pool /Common/CSWEB-NSTICK and member 10.10.97.27:443 Mar 4 10:55:32 ASH1-PROD3900-01 info tmm[11443]: Rule /Common/Persistence-logger : Request from client: 172.21.81.144:57111 contains no persistence cookie on vip /Common/CSWEB-PERSISTENCE-TEST; request was assigned to pool /Common/CSWEB-NSTICK and member 10.12.34.107:443 Mar 4 10:55:32 ASH1-PROD3900-01 info tmm[11443]: Rule /Common/Persistence-logger : Request from client: 172.21.81.144:57111 contains no persistence cookie on vip /Common/CSWEB-PERSISTENCE-TEST; request was assigned to pool /Common/CSWEB-NSTICK and member 10.12.34.108:443

AS you can see the connections bounces from one node to the other since it cannot find a "cookie" . It is assigning the default pool which has a persist none before calling it.

Is there something i might be doing wrong? it looks like the F5 is NOT inserting the cookie properly or at all...

any help is appreciated