Could be a simple case of your session on that one server being reset due to its terminal services configuration. IE, it may have a setting which says that after 5 hours in a disconnected state, your session will be reset. The other one may have a more relaxed configuration which never resets your connection. To check have a look as such:
To set time-out settings for disconnected, active, and idle sessions
Open Terminal Services Configuration.
In the console tree, click Connections.
In the details pane, right-click the connection for which you want to modify time-out settings, and then click Properties.
On the Sessions tab, above End a disconnected session, select the Override user settings check box.
This allows you to configure time-out settings for the connection.
Configure the following time-out settings as appropriate:
In End a disconnected session, select the maximum amount of time that a disconnected session remains on the server. When the time limit is reached, the disconnected session ends. When a session ends, it is permanently deleted from the server. Select Never to allow disconnected sessions to remain on the server indefinitely.
In Active session limit, select the maximum amount of time that a user's session can remain active on the server. When the time limit is reached, either the user is disconnected from the session or the session ends. When a session ends, it is permanently deleted from the server. Select Never to allow the session to continue indefinitely.
In Idle session limit, select the maximum amount of time that an idle session (session without client activity) remains on the server. When the time limit is reached, either the user is disconnected from the session or the session ends. When a session ends, it is permanently deleted from the server. Select Never to allow idle sessions to remain on the server indefinitely.
Claudius (What certifications??)