sutliff1805 can you please write more details on your findings?
- Did you have the WSUS server set via "Group Policy" or "Group Policy Preferences"?
- Was the GPO targeted to all clients, if so were they all affected or just some?
- Where exactly did you see the "UpdateServiceUrlAlternate" set as blank, in the GPO?
- What have you set in the client settings on "Allow clients to download delta content"? Yes or No?
I'm also fighting a similar issue, it occurs only on some devices, where the GPOs that I have in the environment are targeted to all client devices, but I have not seen a GPO that would set WSUS nor the UpdateServiceUrlAlternate.
As for your comment that you saw "UpdateServiceUrlAlternate" set to blank, I can see in the WUAHandler.log on the affected devices, that there is no entry for "UpdateServiceUrlAlternate" and at that moment the registry entry for "UpdateServiceUrlAlternate" is no present.