I've seen this a couple times myself - but only on one of my virtual
machines I use for testing. If my memory is correct - I just re-ran the
utility a few times and it eventually finished. I'm sure it has a lot of
work to do the first time... and much less on subsequent successful runs.
Also, the reason it is the SQL process using CPU and not anything WSUS
related is because the metadata it is cleaning up is inside SQL... so there
really isn't much wsusutil does except fire off a SQL job.
Happy New Year!
MVP - Windows Server (WSUS)