With September 2022 CU/PU additional steps might be required to prevent unexpected problems after applying the updates.
The following information is included in the KB articles for SharePoint 2013, 2016, 2019 and Subscription Edition:
Known issues in this update
- Some Web Part Pages Web Service methods may be affected after you apply the September 2022 security update. For more information, see Web Part Pages Web Service methods may be blocked after applying the September 2022 security update for SharePoint Server (KB5017733).
- Some SharePoint 2010 workflow scenarios may be blocked. For more information, see SharePoint 2010 workflows may be blocked by enhanced security policy (KB5017760).
- This security update introduces a change in SharePoint Server that will affect customers who use the Document Generation capability in Nintex Workflow. Nintex Workflow customers must take additional action after this security update is installed to make sure that workflows can be published and run. For more information, see https://go.microsoft.com/fwlink/?LinkId=2206156. For support for Nintex Workflow, contact Nintex.
Important: we recommend to evaluate all SharePoint updates in a test environment against all business critical functions and processes before applying in production as SharePoint fixes cannot be uninstalled.
More details in my blog post about SharePoint Patching Best Practices.