So, has this issue ever been solved? Having the same complaint from my users about having to login each time they access a document in SharePoint. Thanks, Steve
Welcome to the forum.
Your post indicates a possible intranet sites permission issue with your user's internet browser setting, specifically if the browser in question is Internet Explorer.
To start on the troubleshooting, please have those users change the internet browser they are using for test.
(Firefox and Chrome will be good choices)
If the issue clears then they can continue to use those browsers or make changes to IE settings.
Here is a third party article with some information. Link