Add more information on the known issues

README.md

@@ -38,7 +38,10 @@ Place the widget in a data view, list view or template grid with a data source t
 We are actively maintaining this widget, please report any issues or suggestion for improvement at https://github.com/mendixlabs/rich-text/issues
 
 ### Known issues
-Only partially compatible with Mendix 7.6 due to a known Mendix bug.
+Due to a bug in Mendix 7.6, the React lifecycle method componentWillUnmount is no longer called. 
+This perpetuates events even after the widget has been destroyed, causing a noticeable effect on subsequent editor performance.
+It also prevents the onChange action from being called when a user navigates to a different page.
+This issue shall be fixed in Mendix 7.8
 
 ## Development
 Prerequisite: Install git, node package manager, webpack CLI, grunt CLI, Karma CLI