diff --git a/src/mux_h2.c b/src/mux_h2.c
index 58a5049..e0ee0c7 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -5258,7 +5258,7 @@
 	if (h2c->flags & H2_CF_SHTS_UPDATED) {
 		/* was sent above */
 		h2c->flags |= H2_CF_DTSU_EMITTED;
-		h2c->flags &= H2_CF_SHTS_UPDATED;
+		h2c->flags &= ~H2_CF_SHTS_UPDATED;
 	}
 
 	if (es_now) {