diff --git a/src/mux_quic.c b/src/mux_quic.c
index 2a28a5155..981235520 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -136,6 +136,7 @@ static int qcs_push_frame(struct qcs *qcs, struct buffer *payload, int fin, uint
 		goto err;
 
 	total = b_force_xfer(buf, payload, to_xfer);
+	/* FIN is positioned only when the buffer has been totally emptied. */
 	fin = fin && !b_data(payload);
 	frm->type = QUIC_FT_STREAM_8;
 	if (fin)
@@ -177,16 +178,7 @@ static int qc_send(struct qcc *qcc)
 		struct qcs *qcs = container_of(node, struct qcs, by_id);
 		struct buffer *buf = &qcs->tx.buf;
 		if (b_data(buf)) {
-			char fin = 0;
-
-			/* if FIN is activated, ensure the buffer to
-			 * send is the last
-			 */
-			if (qcs->flags & QC_SF_FIN_STREAM) {
-				BUG_ON(b_data(&qcs->tx.buf) < b_data(buf));
-				fin = (b_data(&qcs->tx.buf) - b_data(buf) == 0);
-			}
-
+			char fin = qcs->flags & QC_SF_FIN_STREAM;
 			ret = qcs_push_frame(qcs, buf, fin, qcs->tx.offset);
 			if (ret < 0)
 				ABORT_NOW();