This can happen when you clone Windows endpoints from a template when the template does not account for this problem.
WSUS uses the SusClientId to identify unique devices and then associate the computer’s hostname to the unique identifier for display purposes. The problem is that if SusClientId on several machines are the same and that is what is used by WSUS, then when they report into WSUS conflicts will arise, causing unexpected errors.
How to fix. Run the following from a command prompt as an admin
#Stop the Automatic Updates service
sc stop wuauserv
#Not in command prompt, but delete the SUSclientID registry key from the following location:
#Start the Automatic Updates service
sc start wuauserv
#Re-register windows client in WUSS
wuauclt /resetauthorization /detectnow