diff --git a/srsenb/src/stack/upper/s1ap.cc b/srsenb/src/stack/upper/s1ap.cc
index 55bbaef8e..6a153673a 100644
--- a/srsenb/src/stack/upper/s1ap.cc
+++ b/srsenb/src/stack/upper/s1ap.cc
@@ -1078,7 +1078,7 @@ bool s1ap::send_error_indication(const asn1::s1ap::cause_c& cause,
   if (enb_ue_s1ap_id.has_value()) {
     container.enb_ue_s1ap_id.value = enb_ue_s1ap_id.value();
     ue* user_ptr                   = users.find_ue_enbid(enb_ue_s1ap_id.value());
-    rnti                           = user_ptr != nullptr ? user_ptr->ctxt.enb_ue_s1ap_id : SRSRAN_INVALID_RNTI;
+    rnti                           = user_ptr != nullptr ? user_ptr->ctxt.rnti : SRSRAN_INVALID_RNTI;
   }
   container.mme_ue_s1ap_id_present = mme_ue_s1ap_id.has_value();
   if (mme_ue_s1ap_id.has_value()) {
@@ -1582,7 +1582,7 @@ bool s1ap::sctp_send_s1ap_pdu(const asn1::s1ap::s1ap_pdu_c& tx_pdu, uint32_t rnt
   }
 
   if (rnti != SRSRAN_INVALID_RNTI) {
-    logger.info(buf->msg, buf->N_bytes, "Tx S1AP SDU, %s, rnti=0x%x", rnti, procedure_name);
+    logger.info(buf->msg, buf->N_bytes, "Tx S1AP SDU, %s, rnti=0x%x", procedure_name, rnti);
   } else {
     logger.info(buf->msg, buf->N_bytes, "Tx S1AP SDU, %s", procedure_name);
   }
@@ -1600,7 +1600,7 @@ bool s1ap::sctp_send_s1ap_pdu(const asn1::s1ap::s1ap_pdu_c& tx_pdu, uint32_t rnt
                                 0);
   if (n_sent == -1) {
     if (rnti != SRSRAN_INVALID_RNTI) {
-      logger.error("Error: Failure at Tx S1AP SDU, %s, rnti=0x%x", rnti, procedure_name);
+      logger.error("Error: Failure at Tx S1AP SDU, %s, rnti=0x%x", procedure_name, rnti);
     } else {
       logger.error("Error: Failure at Tx S1AP SDU, %s", procedure_name);
     }
diff --git a/srsenb/test/upper/s1ap_test.cc b/srsenb/test/upper/s1ap_test.cc
index fd5d9e13d..76106313a 100644
--- a/srsenb/test/upper/s1ap_test.cc
+++ b/srsenb/test/upper/s1ap_test.cc
@@ -78,7 +78,9 @@ struct rrc_tester : public rrc_dummy {
     *erabs_modified         = next_erabs_modified;
     *erabs_failed_to_modify = next_erabs_failed_to_modify;
   }
+  void release_ue(uint16_t rnti) override { last_released_rnti = rnti; }
 
+  uint16_t              last_released_rnti = SRSRAN_INVALID_RNTI;
   std::vector<uint16_t> next_erabs_modified, next_erabs_failed_to_modify;
 };
 
@@ -161,7 +163,7 @@ void add_rnti(s1ap& s1ap_obj, mme_dummy& mme)
   TESTASSERT(s1ap_pdu.successful_outcome().proc_code == ASN1_S1AP_ID_INIT_CONTEXT_SETUP);
 }
 
-enum class test_event { success, wrong_erabid_mod };
+enum class test_event { success, wrong_erabid_mod, wrong_mme_s1ap_id };
 
 void test_s1ap_erab_setup(test_event event)
 {
@@ -202,19 +204,34 @@ void test_s1ap_erab_setup(test_event event)
                            0x00, 0x24, 0x00, 0x06, 0x0A, 0x00, 0x09, 0x3C, 0x01, 0x00};
   // 00 06 00 1E 00 00 03 00 00 00 02 00 01 00 08 00 02 00 01 00 1E 00 0B 00 00 24 00 06 0A 00 09 3C 01 00
   if (event == test_event::wrong_erabid_mod) {
-    mod_req_msg[sizeof(mod_req_msg) - 6] = 0x0C; // E-RAB id == 6
+    mod_req_msg[sizeof(mod_req_msg) - 6] = 0x0C; // E-RAB id = 6
     rrc.next_erabs_failed_to_modify.push_back(6);
+  } else if (event == test_event::wrong_mme_s1ap_id) {
+    mod_req_msg[12] = 0x02; // MME-UE-S1AP-ID = 2
   } else {
     rrc.next_erabs_modified.push_back(5);
   }
   sdu = srsran::make_byte_buffer();
   memcpy(sdu->msg, mod_req_msg, sizeof(mod_req_msg));
   sdu->N_bytes = sizeof(mod_req_msg);
+  TESTASSERT(rrc.last_released_rnti == SRSRAN_INVALID_RNTI);
   TESTASSERT(s1ap_obj.handle_mme_rx_msg(std::move(sdu), mme_addr, rcvinfo, flags));
   sdu = mme.read_msg();
   TESTASSERT(sdu->N_bytes > 0);
   asn1::cbit_ref cbref{sdu->msg, sdu->N_bytes};
   TESTASSERT(s1ap_pdu.unpack(cbref) == SRSRAN_SUCCESS);
+
+  if (event == test_event::wrong_mme_s1ap_id) {
+    // See TS 36.413, Section 10.6 - Handling of AP ID
+    TESTASSERT(s1ap_pdu.type().value == asn1::s1ap::s1ap_pdu_c::types_opts::init_msg);
+    TESTASSERT(s1ap_pdu.init_msg().proc_code == ASN1_S1AP_ID_ERROR_IND);
+    auto& protocol_ies = s1ap_pdu.init_msg().value.error_ind().protocol_ies;
+    TESTASSERT(protocol_ies.mme_ue_s1ap_id_present and protocol_ies.mme_ue_s1ap_id.value.value == 2);
+    TESTASSERT(protocol_ies.enb_ue_s1ap_id_present and protocol_ies.enb_ue_s1ap_id.value.value == 1);
+    TESTASSERT(rrc.last_released_rnti == 0x46);
+    return;
+  }
+
   TESTASSERT(s1ap_pdu.type().value == asn1::s1ap::s1ap_pdu_c::types_opts::successful_outcome);
   TESTASSERT(s1ap_pdu.successful_outcome().proc_code == ASN1_S1AP_ID_ERAB_MODIFY);
   auto& protocol_ies = s1ap_pdu.successful_outcome().value.erab_modify_resp().protocol_ies;
@@ -227,13 +244,13 @@ void test_s1ap_erab_setup(test_event event)
     TESTASSERT(erab_item.cause.type().value == asn1::s1ap::cause_c::types_opts::radio_network);
     TESTASSERT(erab_item.cause.radio_network().value == asn1::s1ap::cause_radio_network_opts::unknown_erab_id);
     return;
-  } else {
-    TESTASSERT(protocol_ies.erab_modify_list_bearer_mod_res_present);
-    TESTASSERT(not protocol_ies.erab_failed_to_modify_list_present);
-    TESTASSERT(protocol_ies.erab_modify_list_bearer_mod_res.value.size() == 1);
-    TESTASSERT(protocol_ies.erab_modify_list_bearer_mod_res.value[0].value.erab_modify_item_bearer_mod_res().erab_id ==
-               5);
   }
+
+  TESTASSERT(protocol_ies.erab_modify_list_bearer_mod_res_present);
+  TESTASSERT(not protocol_ies.erab_failed_to_modify_list_present);
+  TESTASSERT(protocol_ies.erab_modify_list_bearer_mod_res.value.size() == 1);
+  auto& erab_item = protocol_ies.erab_modify_list_bearer_mod_res.value[0].value.erab_modify_item_bearer_mod_res();
+  TESTASSERT(erab_item.erab_id == 5);
 }
 
 int main(int argc, char** argv)
@@ -248,4 +265,5 @@ int main(int argc, char** argv)
 
   test_s1ap_erab_setup(test_event::success);
   test_s1ap_erab_setup(test_event::wrong_erabid_mod);
+  test_s1ap_erab_setup(test_event::wrong_mme_s1ap_id);
 }
\ No newline at end of file