You are getting the error code - 50020 when you try to install the following Windows updates to the endpoints.
The problem is due to the following reason.
Microsoft has acknowledged this in an official statement that "Microsoft and Sophos have identified an issue on devices with Sophos Endpoint Protection installed and managed by either Sophos Central or Sophos Enterprise Console (SEC) that may cause the system to freeze or hang upon restart after installing this update."
To resolve this issue, decline the mentioned Wndows updates to the endpoints. You can decline the updates from Patches > Missing Patches > (select the updates) > Mark as > 'Declined' and select the target computers for which the update has to be declined.
Reference link to the official KB document by Sophos: https://community.sophos.com/kb/en-us/133945
If problem persists, contact support