diff --git a/src/amf/context.c b/src/amf/context.c
index fae77239d2..72d30ad1c6 100644
--- a/src/amf/context.c
+++ b/src/amf/context.c
@@ -1050,6 +1050,28 @@ void amf_ue_new_guti(amf_ue_t *amf_ue)
         return;
     }
 
+    /*
+     * TS24.501
+     * 5.3.3 Temporary identities
+     *
+     * The AMF shall assign a new 5G-GUTI for a particular UE:
+     *
+     * a) during a successful initial registration procedure;
+     * b) during a successful registration procedure
+     *    for mobility registration update; and
+     * c) after a successful service request procedure invoked
+     *    as a response to a paging request from the network and
+     *    before the release of the N1 NAS signalling connection
+     *    as specified in subclause 5.4.4.1.
+     *
+     * The AMF should assign a new 5G-GUTI for a particular UE
+     * during a successful registration procedure
+     * for periodic registration update.
+     *
+     * The AMF may assign a new 5G-GUTI at any time for a particular UE
+     * by performing the generic UE configuration update procedure.
+     */
+
     memset(&amf_ue->next.guti, 0, sizeof(ogs_nas_5gs_guti_t));
 
     ogs_assert(amf_ue->guami);
@@ -1075,6 +1097,28 @@ void amf_ue_confirm_guti(amf_ue_t *amf_ue)
         ogs_assert(amf_m_tmsi_free(amf_ue->current.m_tmsi) == OGS_OK);
     }
 
+    /*
+     * TS24.501
+     * 5.3.3 Temporary identities
+     *
+     * The AMF shall assign a new 5G-GUTI for a particular UE:
+     *
+     * a) during a successful initial registration procedure;
+     * b) during a successful registration procedure
+     *    for mobility registration update; and
+     * c) after a successful service request procedure invoked
+     *    as a response to a paging request from the network and
+     *    before the release of the N1 NAS signalling connection
+     *    as specified in subclause 5.4.4.1.
+     *
+     * The AMF should assign a new 5G-GUTI for a particular UE
+     * during a successful registration procedure
+     * for periodic registration update.
+     *
+     * The AMF may assign a new 5G-GUTI at any time for a particular UE
+     * by performing the generic UE configuration update procedure.
+     */
+
     /* Copying from Current to Next Guti */
     amf_ue->current.m_tmsi = amf_ue->next.m_tmsi;
     memcpy(&amf_ue->current.guti,
@@ -2197,7 +2241,8 @@ void amf_update_allowed_nssai(amf_ue_t *amf_ue)
         for (i = 0; i < amf_ue->num_of_slice; i++) {
             ogs_slice_data_t *slice = &amf_ue->slice[i];
             ogs_nas_s_nssai_ie_t *allowed =
-                &amf_ue->allowed_nssai.s_nssai[i];
+                &amf_ue->allowed_nssai.
+                    s_nssai[amf_ue->allowed_nssai.num_of_s_nssai];
 
             if (slice->default_indicator == true) {
                 allowed->sst = slice->s_nssai.sst;
diff --git a/src/amf/gmm-handler.c b/src/amf/gmm-handler.c
index 10df53eee2..8bc30d63d9 100644
--- a/src/amf/gmm-handler.c
+++ b/src/amf/gmm-handler.c
@@ -211,7 +211,27 @@ int gmm_handle_registration_request(amf_ue_t *amf_ue,
         amf_ue->nhcc = 1;
     }
 
-    /* Create New GUTI */
+    /*
+     * TS24.501
+     * 5.3.3 Temporary identities
+     *
+     * The AMF shall assign a new 5G-GUTI for a particular UE:
+     *
+     * a) during a successful initial registration procedure;
+     * b) during a successful registration procedure
+     *    for mobility registration update; and
+     * c) after a successful service request procedure invoked
+     *    as a response to a paging request from the network and
+     *    before the release of the N1 NAS signalling connection
+     *    as specified in subclause 5.4.4.1.
+     *
+     * The AMF should assign a new 5G-GUTI for a particular UE
+     * during a successful registration procedure
+     * for periodic registration update.
+     *
+     * The AMF may assign a new 5G-GUTI at any time for a particular UE
+     * by performing the generic UE configuration update procedure.
+     */
     amf_ue_new_guti(amf_ue);
 
     ogs_debug("    OLD TAI[PLMN_ID:%06x,TAC:%d]",
diff --git a/src/amf/gmm-sm.c b/src/amf/gmm-sm.c
index 58b78b5642..a2b22ce723 100644
--- a/src/amf/gmm-sm.c
+++ b/src/amf/gmm-sm.c
@@ -305,7 +305,27 @@ static void common_register_state(ogs_fsm_t *s, amf_event_t *e)
         case OGS_NAS_5GS_CONFIGURATION_UPDATE_COMPLETE:
             ogs_debug("[%s] Configuration update complete", amf_ue->supi);
 
-            /* Confirm GUTI */
+            /*
+             * TS24.501
+             * 5.3.3 Temporary identities
+             *
+             * The AMF shall assign a new 5G-GUTI for a particular UE:
+             *
+             * a) during a successful initial registration procedure;
+             * b) during a successful registration procedure
+             *    for mobility registration update; and
+             * c) after a successful service request procedure invoked
+             *    as a response to a paging request from the network and
+             *    before the release of the N1 NAS signalling connection
+             *    as specified in subclause 5.4.4.1.
+             *
+             * The AMF should assign a new 5G-GUTI for a particular UE
+             * during a successful registration procedure
+             * for periodic registration update.
+             *
+             * The AMF may assign a new 5G-GUTI at any time for a particular UE
+             * by performing the generic UE configuration update procedure.
+             */
             if (amf_ue->next.m_tmsi) {
                 amf_ue_confirm_guti(amf_ue);
             } else {
@@ -988,7 +1008,27 @@ void gmm_state_initial_context_setup(ogs_fsm_t *s, amf_event_t *e)
 
             CLEAR_AMF_UE_TIMER(amf_ue->t3550);
 
-            /* Confirm GUTI */
+            /*
+             * TS24.501
+             * 5.3.3 Temporary identities
+             *
+             * The AMF shall assign a new 5G-GUTI for a particular UE:
+             *
+             * a) during a successful initial registration procedure;
+             * b) during a successful registration procedure
+             *    for mobility registration update; and
+             * c) after a successful service request procedure invoked
+             *    as a response to a paging request from the network and
+             *    before the release of the N1 NAS signalling connection
+             *    as specified in subclause 5.4.4.1.
+             *
+             * The AMF should assign a new 5G-GUTI for a particular UE
+             * during a successful registration procedure
+             * for periodic registration update.
+             *
+             * The AMF may assign a new 5G-GUTI at any time for a particular UE
+             * by performing the generic UE configuration update procedure.
+             */
             if (amf_ue->next.m_tmsi) {
                 amf_ue_confirm_guti(amf_ue);
             } else {
diff --git a/src/amf/ngap-handler.c b/src/amf/ngap-handler.c
index 3b7b07fa8c..9e402908cf 100644
--- a/src/amf/ngap-handler.c
+++ b/src/amf/ngap-handler.c
@@ -923,7 +923,27 @@ void ngap_handle_initial_context_setup_response(
     if (paging_ongoing == true) {
         gmm_configuration_update_command_param_t param;
 
-        /* Create New GUTI */
+        /*
+         * TS24.501
+         * 5.3.3 Temporary identities
+         *
+         * The AMF shall assign a new 5G-GUTI for a particular UE:
+         *
+         * a) during a successful initial registration procedure;
+         * b) during a successful registration procedure
+         *    for mobility registration update; and
+         * c) after a successful service request procedure invoked
+         *    as a response to a paging request from the network and
+         *    before the release of the N1 NAS signalling connection
+         *    as specified in subclause 5.4.4.1.
+         *
+         * The AMF should assign a new 5G-GUTI for a particular UE
+         * during a successful registration procedure
+         * for periodic registration update.
+         *
+         * The AMF may assign a new 5G-GUTI at any time for a particular UE
+         * by performing the generic UE configuration update procedure.
+         */
         amf_ue_new_guti(amf_ue);
 
         memset(&param, 0, sizeof(param));