Well, I don't have the Admin>forum>Thred tags because I do not subscribe to the forum service. I prefer the forums from SMF. The only forum items we use are the news and the applications.
That being said...
The Application settings are set for Guild Only, Private, Backup Raider or higher rank. The members having the issue are all a member of the correct guild. Their names appear in the Top area of the threads showing they should be able to view them.
When the click on the Applications link in the menu, they are taken to the application threads, but if they click on details, they are taken to the news forums thread list.