no load-balancing by LB::reselect pool $NewPool;

If I am building a session entry, do I need to delete that in the LB_FAILED event? We are seeing that although I have a reselect in the LB_FAILED event, traffic continues to be sent to the destination pool member until the LTM marks it down. Would it benefit me to delete the session entry when the LB_FAILED event is kicked off? Does this event get triggered for persistent connections? Here's what I'd like to do:

when LB_SELECTED {
  log "Server [IP::remote_addr] selected!"
}
when LB_FAILED {
  log "Server [IP::remote_addr] Failed!"
  set lbfailed 1
  session delete uie $trimID
  LB::reselect pool MyPool
}

BTW, the session entry is the server IP address for the key which is the jsessionID. It is set on the HTTP_RESPONSE event for new connections and when LB_FAILED is triggered. I am currently deleting the session in the HTTP_RESPONSE event only when the lbfailed variable is true.