diff --git a/cluster/cluster.go b/cluster/cluster.go
index 13848bae..590b8c06 100644
--- a/cluster/cluster.go
+++ b/cluster/cluster.go
@@ -648,6 +648,7 @@ func (c *cluster) Shutdown() error {
 		c.raft.Shutdown()
 	}
 
+	// TODO: here might some situations, where the manager is still need from the synchronize loop and will run into a panic
 	c.manager = nil
 	c.raft = nil