The IT has confirmed that there is nothing in the program that causes the frequent signing out.
Well, I'm not sure how to break the news to them
It's still an issue, I've been logging in all day. Once my status is displayed as logged in on the forum home page, I open a sub-forum and my status is updated to logged out. From there it's an endless cycle of logging in and opening a sub forum only to find I'm no longer logged in.
This only occurs with IE 11, so maybe the code has some incompatibility with it.