I have the same issue it sounds like on a 2016 server, only way I saw to resolve was to resolve was to Uninstall the July Cummulative update. I even installed the update MS released at the end of july - kb4346877 and got the same issue. Is Ivanti working with MS on the issue?
To resolve the issue, we removed the .NET Framework 4.7.1 updates 4054566 & 4338605 and then ran the clean-up steps to clear ASP.NET temporary folder.
After doing this, Windows Authentication started working again.
Alternately, you could upgrade to Xtraction 2018 HTML version and forget about Flash altogether.
Upgrading to 2018.2 HTML5 version may very well be the "long-term" solution to this issue. Unfortunately, the short-term solution may have to be don't apply those .Net updates, since 2018.2 has not yet been released. However, it SHOULD be released soon.
Thanks I was able to clear the asp.net temp folder and install the 2016 OS cumulative update and Xtract still worked