kamailio doesn't forward the ACK

UAC
1. Receive 200 OK
SIP/2.0 200 OK
| INFO3 | cb_rcv2xx (id=2)^M
| INFO1 | cb_nict_kill_transaction (id=2)^M
| INFO4 | sipevent evt: method called!

2. Send ACK

3. Receive 200 OK again
| INFO1 | 2xx restransmission receveid.^M
| INFO1 | Message sent:
4. Send ACK again
| INFO1 | ACK restransmission sent.