By removing the WSUS registry keys, the system will check in with WSUS and obtain new ID’s. This is at least one of the blogs that identifies how to resolve this, that I have used in the past. The most likely reason for this is a duplicate SID, likely resulting from a lack of SysPrep when the machine was originally created.
However, the computer does not show up in any reporting. Upon investigation of the systems individually, it is verified that the correct GPO is being applied, the correct WSUS settings exist, etc. Recently I ran into an issue where our WSUS server is not showing all expected systems in the console.
