Tweak release-notes/5.40.0.md

release-notes/5.40.0.md

 # CiviCRM 5.40.0
 
-Released August 4, 2021
+Released August 5, 2021
 
 - **[Synopsis](#synopsis)**
 - **[Features](#features)**
@@ -454,6 +454,10 @@ Released August 4, 2021
 
 ### CiviContribute
 
+- **Error submitting contribution form if ""is_monetary=0""
+  ([dev/wordpress#109](https://lab.civicrm.org/dev/wordpress/-/issues/109):
+  [#20929](https://github.com/civicrm/civicrm-core/pull/20929))**
+
 - **Can't remove previously-added currencies
   ([dev/financial#175](https://lab.civicrm.org/dev/financial/-/issues/175):
   [20627](https://github.com/civicrm/civicrm-core/pull/20627))**