diff --git a/src/quic_conn.c b/src/quic_conn.c
index c67ae6d54..529e99777 100644
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -5158,40 +5158,38 @@ struct task *qc_process_timer(struct task *task, void *ctx, unsigned int state)
 
 	if (qc->path->in_flight) {
 		pktns = quic_pto_pktns(qc, qc->state >= QUIC_HS_ST_CONFIRMED, NULL);
-		if (qc_notify_send(qc)) {
-			pktns->tx.pto_probe = QUIC_MAX_NB_PTO_DGRAMS;
+		if (pktns == &qc->pktns[QUIC_TLS_PKTNS_INITIAL]) {
+			if (qc_may_probe_ipktns(qc)) {
+				qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
+				pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
+				TRACE_STATE("needs to probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
+			}
+			else {
+				TRACE_STATE("Cannot probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
+			}
+			if (qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE].tx.in_flight) {
+				qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
+				qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE].flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
+				TRACE_STATE("needs to probe Handshake packet number space", QUIC_EV_CONN_TXPKT, qc);
+			}
 		}
-		else {
-			if (pktns == &qc->pktns[QUIC_TLS_PKTNS_INITIAL]) {
+		else if (pktns == &qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE]) {
+			TRACE_STATE("needs to probe Handshake packet number space", QUIC_EV_CONN_TXPKT, qc);
+			qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
+			pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
+			if (qc->pktns[QUIC_TLS_PKTNS_INITIAL].tx.in_flight) {
 				if (qc_may_probe_ipktns(qc)) {
-					qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
-					pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
+					qc->pktns[QUIC_TLS_PKTNS_INITIAL].flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
 					TRACE_STATE("needs to probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
 				}
 				else {
 					TRACE_STATE("Cannot probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
 				}
-				if (qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE].tx.in_flight) {
-					qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
-					qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE].flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
-					TRACE_STATE("needs to probe Handshake packet number space", QUIC_EV_CONN_TXPKT, qc);
-				}
 			}
-			else if (pktns == &qc->pktns[QUIC_TLS_PKTNS_HANDSHAKE]) {
-				TRACE_STATE("needs to probe Handshake packet number space", QUIC_EV_CONN_TXPKT, qc);
-				qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
-				pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
-				if (qc->pktns[QUIC_TLS_PKTNS_INITIAL].tx.in_flight) {
-					if (qc_may_probe_ipktns(qc)) {
-						qc->pktns[QUIC_TLS_PKTNS_INITIAL].flags |= QUIC_FL_PKTNS_PROBE_NEEDED;
-						TRACE_STATE("needs to probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
-					}
-					else {
-						TRACE_STATE("Cannot probe Initial packet number space", QUIC_EV_CONN_TXPKT, qc);
-					}
-				}
-			}
-			else if (pktns == &qc->pktns[QUIC_TLS_PKTNS_01RTT]) {
+		}
+		else if (pktns == &qc->pktns[QUIC_TLS_PKTNS_01RTT]) {
+			/* Wake up upper layer if waiting to send new data. */
+			if (!qc_notify_send(qc)) {
 				TRACE_STATE("needs to probe 01RTT packet number space", QUIC_EV_CONN_TXPKT, qc);
 				qc->flags |= QUIC_FL_CONN_RETRANS_NEEDED;
 				pktns->flags |= QUIC_FL_PKTNS_PROBE_NEEDED;