c:\windows\temp not getting backed up

I have looked a couple of clients, and they are all the same.  Even if I create a policy specifically for C:\Windows\Temp, it doesn't back it up.  The backup finishes with status 0, I can browse the restore, and see nothing except the directory itself.

Anyone know why?  I don't see c:\Windows\Temp in any exclude lists.

Using 7.5.0.5, have also seen on 7.5.0.4.  Windows 2008 R2 clients and servers.