diff --git a/src/h3.c b/src/h3.c
index 3c9463d92..2aa4fa78e 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -2378,20 +2378,23 @@ static int h3_finalize(void *ctx)
 
 	qcs = qcc_init_stream_local(qcc, 0);
 	if (!qcs) {
+		/* Error must be set by qcc_init_stream_local(). */
+		BUG_ON(!(qcc->flags & QC_CF_ERRL));
 		TRACE_ERROR("cannot init control stream", H3_EV_H3C_NEW, qcc->conn);
 		goto err;
 	}
 
 	h3c->ctrl_strm = qcs;
 
-	if (h3_control_send(qcs, h3c) < 0)
+	if (h3_control_send(qcs, h3c) < 0) {
+		qcc_set_error(qcc, H3_ERR_INTERNAL_ERROR, 1);
 		goto err;
+	}
 
 	TRACE_LEAVE(H3_EV_H3C_NEW, qcc->conn);
 	return 0;
 
  err:
-	qcc_set_error(qcc, H3_ERR_INTERNAL_ERROR, 1);
 	TRACE_DEVEL("leaving on error", H3_EV_H3C_NEW, qcc->conn);
 	return 1;
 }
diff --git a/src/mux_quic.c b/src/mux_quic.c
index 9c8f55e7e..15a2ed076 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -617,8 +617,8 @@ struct qcs *qcc_init_stream_local(struct qcc *qcc, int bidi)
 
 	qcs = qcs_new(qcc, *next, type);
 	if (!qcs) {
-		TRACE_LEAVE(QMUX_EV_QCS_NEW, qcc->conn);
 		qcc_set_error(qcc, QC_ERR_INTERNAL_ERROR, 0);
+		TRACE_DEVEL("leaving on error", QMUX_EV_QCS_NEW, qcc->conn);
 		return NULL;
 	}