Windows clients failing with error code 58, and NB/PBX services unable to be restarted.

I recently encountered an issue with a lot of Windows NetBackup client backups failing with error code 58...can't connect to client. We thought that perhaps it was due to a bad configuration on the 7.7.3 client package being deployed by the Windows team, but in our troubleshooting we discovered that we were not able to stop/start the NBU or PBX services on the windows clients. While a reboot fixed the problem, it looks like the culprit was the Windows July 2018 patch bundle, KB4338815 .