Access denied when moving up one folder

I have a situation with multiple users where they go to save a file to a subfolder on a network drive, click the icon to move up one folder, and immediately they get “Access denied”. However, they have full permissions to the parent folder and inherited permissions to the subfolders.

For example, I try to save Thing.txt to G:\Stuff1\Stuff2 and in the Save As dialog box, I click the little icon for going up one folder to Stuff1. Immediately, there is an “Access denied” message. However, If I save to G:\ and then go down to Stuff1, there is no problem.

The permissions are full control for the users on this network drive. What could be going on here?