I'm guessing our issue is just a bug with latest update, which included the desktop notifications.
I was able to 'fix' by uninstalling, and also dropping the persisting columns prefixed with 'dbtech_vbshout' from the vbulletin 'user' table, before reinstalling a modified version without desktop notifications.
I am sure this is unsupported by the dev and they will release a fix in the near future. I'm just not patient
Sure would be nice to have those desktop notifications though!