We've continued to scan the site and the server. We're clean. It is highly unusual that many have NO PROBLEM with the site while others have NOTHING BUT TROUBLE. Whatever it is is NOT coming from us. We continue to monitor but can't find anything we can work on from here. From what we can tell this issue goes away in a couple of days.
That would suggest to me a cookie picked up somewhere with malware. A flush of DNS and cookies might solve the issue.