My Documents Drops Target

I have two workstations that are dropping the "Target" information for the
location of "My Documents". I have pointed the "Target" from the default of
"Cocuments and Settings\username\my documents" to a mapped "P" Drive (P:\).
The mapped drive is pointing to their private working directory on their
local server. I have also synchronized their "P" drives to be made available
off line. When these users login they see their "My Documents" Target
location return to the local default although when changed, throughout their
session the "My Documents" Target is pointing to the P Drive. The P Drive is
mapped to reconnect on login.

WHAT'S UP WITH THAT?