diff --git a/src/mux_h1.c b/src/mux_h1.c
index 886caaaa7..1459fadfa 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -1666,7 +1666,7 @@ static size_t h1_handle_trailers(struct h1s *h1s, struct h1m *h1m, struct htx *h
 			TRACE_ERROR("parsing error, reject H1 message", H1_EV_RX_DATA|H1_EV_RX_TLRS|H1_EV_H1S_ERR, h1s->h1c->conn, h1s);
 			h1_capture_bad_message(h1s->h1c, h1s, h1m, buf);
 		}
-		else if (ret == -2) {
+		else if (ret == -2 || b_data(buf) != *ofs) {
 			TRACE_STATE("RX path congested, waiting for more space", H1_EV_RX_DATA|H1_EV_RX_TLRS|H1_EV_H1S_BLK, h1s->h1c->conn, h1s);
 			h1s->flags |= H1S_F_RX_CONGESTED;
 		}