diff --git a/lib/iscsi/conn.c b/lib/iscsi/conn.c
index 3732537e6..a0833eb0a 100644
--- a/lib/iscsi/conn.c
+++ b/lib/iscsi/conn.c
@@ -1090,13 +1090,23 @@ process_non_read_task_completion(struct spdk_iscsi_conn *conn,
 		 *  the overall transfer length.
 		 */
 		if (task != primary || task->scsi.length != task->scsi.transfer_len) {
-			spdk_del_transfer_task(conn, primary->tag);
-			if (primary->rsp_scsi_status != SPDK_SCSI_STATUS_GOOD) {
-				iscsi_task_copy_from_rsp_scsi_status(&primary->scsi, primary);
+			/* If LUN is removed in the middle of the iSCSI write sequence,
+			 *  primary might complete the write to the initiator because it is not
+			 *  ensured that the initiator will send all data requested by R2Ts.
+			 *
+			 * We check it and skip the following if primary is completed. (see
+			 *  spdk_clear_all_transfer_task() in iscsi.c.)
+			 */
+			if (primary->is_r2t_active) {
+				spdk_del_transfer_task(conn, primary->tag);
+				if (primary->rsp_scsi_status != SPDK_SCSI_STATUS_GOOD) {
+					iscsi_task_copy_from_rsp_scsi_status(&primary->scsi, primary);
+				}
+				spdk_iscsi_task_response(conn, primary);
+				TAILQ_REMOVE(&conn->active_r2t_tasks, primary, link);
+				primary->is_r2t_active = false;
+				spdk_iscsi_task_put(primary);
 			}
-			spdk_iscsi_task_response(conn, primary);
-			TAILQ_REMOVE(&conn->active_r2t_tasks, primary, link);
-			spdk_iscsi_task_put(primary);
 		} else {
 			spdk_iscsi_task_response(conn, task);
 		}
diff --git a/lib/iscsi/iscsi.c b/lib/iscsi/iscsi.c
index dcf65dc5c..0a6d7dea4 100644
--- a/lib/iscsi/iscsi.c
+++ b/lib/iscsi/iscsi.c
@@ -2772,6 +2772,7 @@ add_transfer_task(struct spdk_iscsi_conn *conn, struct spdk_iscsi_task *task)
 	}
 
 	TAILQ_INSERT_TAIL(&conn->active_r2t_tasks, task, link);
+	task->is_r2t_active = true;
 	return 0;
 }
 
@@ -2837,6 +2838,7 @@ del_connection_queued_task(struct spdk_iscsi_conn *conn, void *tailq,
 		if ((lun == NULL || lun == task->scsi.lun) &&
 		    (pdu == NULL || SN32_LT(pdu_tmp->cmd_sn, pdu->cmd_sn))) {
 			TAILQ_REMOVE(head, task, link);
+			task->is_r2t_active = false;
 			if (lun != NULL && spdk_scsi_lun_is_removing(lun)) {
 				spdk_scsi_task_process_null_lun(&task->scsi);
 				spdk_iscsi_task_response(conn, task);
diff --git a/lib/iscsi/task.h b/lib/iscsi/task.h
index d692b9ff8..1dfc5239a 100644
--- a/lib/iscsi/task.h
+++ b/lib/iscsi/task.h
@@ -88,6 +88,7 @@ struct spdk_iscsi_task {
 	uint32_t datain_datasn;
 	uint32_t acked_data_sn; /* next expected datain datasn */
 	uint32_t ttt;
+	bool is_r2t_active;
 
 	uint32_t tag;
 
diff --git a/test/unit/lib/iscsi/conn.c/conn_ut.c b/test/unit/lib/iscsi/conn.c/conn_ut.c
index 774067217..2dc3e68bd 100644
--- a/test/unit/lib/iscsi/conn.c/conn_ut.c
+++ b/test/unit/lib/iscsi/conn.c/conn_ut.c
@@ -384,6 +384,7 @@ process_non_read_task_completion_test(void)
 	primary.rsp_scsi_status = SPDK_SCSI_STATUS_GOOD;
 	primary.scsi.ref = 1;
 	TAILQ_INSERT_TAIL(&conn.active_r2t_tasks, &primary, link);
+	primary.is_r2t_active = true;
 
 	/* First subtask which failed. */
 	task.scsi.length = 4096;
@@ -442,6 +443,7 @@ process_non_read_task_completion_test(void)
 	primary.rsp_scsi_status = SPDK_SCSI_STATUS_GOOD;
 	primary.scsi.ref = 2;
 	TAILQ_INSERT_TAIL(&conn.active_r2t_tasks, &primary, link);
+	primary.is_r2t_active = true;
 
 	process_non_read_task_completion(&conn, &primary, &primary);
 	CU_ASSERT(TAILQ_EMPTY(&conn.active_r2t_tasks));
@@ -449,6 +451,24 @@ process_non_read_task_completion_test(void)
 	CU_ASSERT(primary.scsi.data_transferred == 4096 * 2);
 	CU_ASSERT(primary.rsp_scsi_status == SPDK_SCSI_STATUS_GOOD);
 	CU_ASSERT(primary.scsi.ref == 0);
+
+	/* Further tricky case when the last task completed ws the initial task,
+	 * and the R2T was already terminated.
+	 */
+	primary.scsi.ref = 1;
+	primary.scsi.length = 4096;
+	primary.bytes_completed = 4096 * 2;
+	primary.scsi.data_transferred = 4096 * 2;
+	primary.scsi.transfer_len = 4096 * 3;
+	primary.scsi.status = SPDK_SCSI_STATUS_GOOD;
+	primary.rsp_scsi_status = SPDK_SCSI_STATUS_GOOD;
+	primary.is_r2t_active = false;
+
+	process_non_read_task_completion(&conn, &primary, &primary);
+	CU_ASSERT(primary.bytes_completed == 4096 * 3);
+	CU_ASSERT(primary.scsi.data_transferred == 4096 * 2);
+	CU_ASSERT(primary.rsp_scsi_status == SPDK_SCSI_STATUS_GOOD);
+	CU_ASSERT(primary.scsi.ref == 0);
 }
 
 static void