USB Memory Device drive letter not found

I have found what I believe to be a fault with Windows XP
that could be fixed by a patch de jour from Microsoft?

When a USB memory device is plugged into a Windows XP PC
that is normally connected to a network, and it has drive
letters mapped to a network drive that are not presently
available because the network is unplugged, the drive
letter assigned to the USB device is the same as the
first mapped network drive letter.

A normal user can not easily find this as the mapped
network drive letter does not change it's title to show
the removeable device, but keeps the same description as
the original network share, even if a page refresh (F5)is
requested.

The drivers in use are Microsofts own plug N play drivers.

Has anyone seen this before? I can not find any reference
to it on the Microsoft support pages.