Hello,
I have used DropBox for the last 5+ years and have never had this issue.. My coworker has added a folder within one of our shared folders but I am unable to view locally from the windows app, I am only able to see the folder if I go to dropbox.com or on the mobile app on my iphone..
I have tried making the file available offline, I have checked for any "bad characters" in the file name, checked the sync status/ history on the desktop app, tried having him share that specific folder that is inside of our shared folder etc.. and nothing is working.