diff --git a/src/mux_h1.c b/src/mux_h1.c
index f9bd1d8..455f623 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -3297,8 +3297,10 @@
 		/* We're about to destroy the connection, so make sure nobody attempts
 		 * to steal it from us.
 		 */
-		if (h1c->conn->flags & CO_FL_LIST_MASK)
+		if (h1c->conn->flags & CO_FL_LIST_MASK) {
 			conn_delete_from_tree(&h1c->conn->hash_node->node);
+			h1c->conn->flags &= ~CO_FL_LIST_MASK;
+		}
 
 		HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
 	}