After much digging, our IT contractor found that  although our firewall & security vendor had whitelisted Lacerte, the Lacerte updates were causing it to get blocked again, i.e. not be recognized as the whitelisted entity.  His exact wording was "the updates and an update folder structure got past the whitelisting again. Changes have been made to prevent this now."

That was on July 15th, and we've not seen the issue again, where it had averaged happening at least a couple of times a week before.

Hope this is helpful. It was certainly a frustrating issue!