Question: What action does the network take upon receiving a DETACH ACCEPT message with an EMM cause value of #2 "IMSI unknown in HSS" and a Detach type IE indicating "re-attach not required"?
Option 1: The network changes the current EMM state to EMM-DEREGISTERED.
Option 2: The network does not change the current EMM state.
Option 3: The network stops timer T3422 and enters state EMM-REGISTERED.
Option 4: The network sends a new DETACH REQUEST message.
Explanation: According to the specified condition, if the Detach type IE indicates "re-attach not required" and the EMM cause value is #2 "IMSI unknown in HSS", the network shall not change the current EMM state.