diff --git a/messenger.rst b/messenger.rst
index 65941a449f5..77c0e8bcf4e 100644
--- a/messenger.rst
+++ b/messenger.rst
@@ -1361,6 +1361,11 @@ auto_setup          Whether the table should be created
                     automatically during send / get.       true
 ==================  =====================================  ======================
 
+
+.. note::
+
+    ``redeliver_timeout`` must be set to a greater value than your slowest message duration. Failing to do so will result in messages being started a second time while the first one is still running.
+
 .. versionadded:: 5.1
 
     The ability to leverage PostgreSQL's LISTEN/NOTIFY was introduced