When a UE is registered to the same PLMN or SNPN over 3GPP and non-3GPP access, the UE and the AMF maintain one 5G-GUTI that is common to both 3GPP and non-3GPP access. When the UE is required to re-register to the network, the UE follows the procedures of deregister over both accesses, delete the common shared 5G-GUTI, and re-register over both accesses. The UE needs to perform the above procedures in a graceful sequence. In one novel aspect, the UE triggers the re-registration (either over 3GPP or non-3GPP access) after the completion of deregistration over both 3GPP and non-3GPP access. In addition, the UE deletes the common 5G-GUTI only after the completion of deregistration over both 3GPP and non-3GPP access.