diff --git a/src/mux_h2.c b/src/mux_h2.c
index 1169066..f8b9ecc 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -3007,7 +3007,7 @@
 	 */
 	if (!(cs->conn->flags & CO_FL_ERROR) &&
 	    (h2c->st0 < H2_CS_ERROR) &&
-	    (h2s->flags & (H2_SF_BLK_MBUSY | H2_SF_BLK_MROOM | H2_SF_BLK_MFCTL)))
+	    (h2s->flags & (H2_SF_BLK_MBUSY | H2_SF_BLK_MROOM | H2_SF_BLK_MFCTL)) && (h2s->send_wait || h2s->recv_wait))
 		return;
 
 	if ((h2c->flags & H2_CF_DEM_BLOCK_ANY && h2s->id == h2c->dsi) ||