A partner reported trouble after upgrading from 4.40 to 4.61 and ASP.NET 2.0 on a customer site. Having edit mode inactive for over 30 minutes caused a re-log-in with the result that every change was lost.
You all probably know this but ASP.NET 2.0 changes the time-out from 120 to 30 minutes.
http://weblogs.asp.net/scottgu/archive/2005/11/08/430011.aspx