diff --git a/openair2/RRC/NR/rrc_gNB.c b/openair2/RRC/NR/rrc_gNB.c
index fdd6fb9544..6554490736 100755
--- a/openair2/RRC/NR/rrc_gNB.c
+++ b/openair2/RRC/NR/rrc_gNB.c
@@ -3456,7 +3456,7 @@ static void rrc_DU_process_ue_context_modification_request(MessageDef *msg_p, co
       LOG_I(NR_RRC, "Send first DDD buffer status reporting towards the CU through an ITTI message to gtp-u \n");
       uint8_t drb_id = ue_context_p->ue_context.DRB_configList->list.array[0]->drb_Identity;
       rnti_t rnti   = ue_context_p->ue_context.rnti;
-      int rlc_tx_buffer_space = nr_rlc_get_available_tx_space(rnti, drb_id);
+      int rlc_tx_buffer_space = nr_rlc_get_available_tx_space(rnti, drb_id + 3);
       LOG_I(NR_RRC, "Reported in DDD drb_id:%d, rnti:%d\n", drb_id, rnti);
       MessageDef *msg = itti_alloc_new_message_sized(TASK_RRC_GNB, 0, GTPV1U_DU_BUFFER_REPORT_REQ,
                                      sizeof(gtpv1u_gnb_tunnel_data_req_t));
diff --git a/openair3/ocp-gtpu/gtp_itf.cpp b/openair3/ocp-gtpu/gtp_itf.cpp
index af2a0ee9e8..618cdef23b 100644
--- a/openair3/ocp-gtpu/gtp_itf.cpp
+++ b/openair3/ocp-gtpu/gtp_itf.cpp
@@ -1115,7 +1115,7 @@ static int Gtpv1uHandleGpdu(int h,
 
   if(NR_PDCP_PDU_SN > 0 && NR_PDCP_PDU_SN %5 ==0){
     LOG_D (GTPU, "Create and send DL DATA Delivery status for the previously received PDU, NR_PDCP_PDU_SN: %u \n", NR_PDCP_PDU_SN);
-    int rlc_tx_buffer_space = nr_rlc_get_available_tx_space(ctxt.rnti, rb_id);
+    int rlc_tx_buffer_space = nr_rlc_get_available_tx_space(ctxt.rnti, rb_id + 3);
     LOG_D(GTPU, "Available buffer size in RLC for Tx: %d \n", rlc_tx_buffer_space);
     /*Total size of DDD_status PDU = 1 octet to report extension header length
      * size of mandatory part + 3 octets for highest transmitted/delivered PDCP SN