Reported here, and confirmed by at least one other:
http://www.ztw3.com/forum/forum_entry.php?id=123150
If I map a network drive and access it over the internet via VPN, Alt-Info behaves slightly differently to when it's used on local drives, or even the same drives accessed over a LAN.
If I press the Up or Down key, the Alt-Info box closes instead of displaying the details of the previous or next folder or file.
If I click on another folder or file with the mouse, the Alt-Info box stays open. It also stays open if I scroll the mouse wheel to another file/folder.