Hi not sure if you still have issue - however I would try running this batchfile on a client machine with the wsus issue - as I feel problem could be related to the machines susclientid.
rem Fixes problem with client machines not showing up on the server due to imaging method
reg delete HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate /v AccountDomainSid /f
reg delete HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate /v PingID /f
reg delete HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate /v SusClientId /f
cls
@echo Triggering detection after resetting WSUS client identity
net stop wuauserv
net start wuauserv
wuauclt /resetauthorization /detectnow
