Section: 5.5.2.3.4 Abnormal cases in the UE
Content: The following abnormal cases can be identified: a) Transmission failure of DETACH ACCEPT message indication from lower layers The detach procedure shall be progressed and the UE shall send the DETACH ACCEPT message. b) DETACH REQUEST, other EMM cause values than those treated in clause 5.5.2.3.2 or no EMM cause IE is included, and the Detach type IE indicates "re-attach not required" The UE shall delete any GUTI, TAI list, last visited registered TAI, list of equivalent PLMNs, KSI, shall set the update status to EU2 NOT UPDATED and shall start timer T3402. A UE operating in CS/PS mode 1 or CS/PS mode 2 of operation which is IMSI attached for non-EPS services is still IMSI attached for non-EPS services and shall set the update status to U2 NOT UPDATED. A UE not supporting any of A/Gb mode, Iu mode or N1 mode may enter the state EMM-DEREGISTERED.PLMN-SEARCH in order to perform a PLMN selection according to 3GPP TS 23.122[ Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode ]  [6]; otherwise the UE shall enter the state EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH. A UE supporting A/Gb mode, Iu mode or N1 mode shall - enter the state EMM-DEREGISTERED and attempt to select GERAN, UTRAN, or NR radio access technology and proceed with the appropriate MM, GMM or 5GMM specific procedures. In this case, the UE may disable the E-UTRA capability (see clause 4.5); - enter the state EMM-DEREGISTERED.PLMN-SEARCH in order to perform a PLMN selection according to 3GPP TS 23.122[ Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode ]  [6]; or - enter the state EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH. If A/Gb mode or Iu mode is supported by the UE, the UE shall set the GPRS update status to GU2 NOT UPDATED and shall delete the GMM parameters P-TMSI, P-TMSI signature, RAI, GPRS ciphering key sequence number and shall enter the state GMM-DEREGISTERED. If the UE is operating in single-registration mode, the UE shall in addition set the 5GMM state to 5GMM-DEREGISTERED, 5GS update status to 5U2 NOT UPDATED, and shall delete any 5G-GUTI, last visited registered TAI, TAI list and ngKSI.