Your users are using V10 ajax, correct? I think your problem is a behavior of the ajax client. If users don't explicitly close the ajax sesson by pressing the "close" link in upper right, the session -- and it's selection state -- remain active. The session willl only go away after timeout. So if a user comes back to the document before session timeout, they are reconnected to the same session, including state. In V9 it used to create a whole new session, which was a problem for session CAL users.
So test if using the "close" link makes the problem go away. That is, you will get intial selections every time you enter the doc.
If that's your problem then the next step is to find a workaround that works for you.
BTW, I think the server bookmarks you are seeing are for the session recovery option, and not directly the cause of what you are seeing.