I'm on v2.6.5.0
I've observed this on both my XP & Vista machines, but it seems to be more prevalent on the Vista machine.
Just using the standard, automatic update process and letting it go to updating on restart, I've noticed that sometimes I have to start the app 2 or 3 times for it to finally launch and go through the update. In other words, it's like the desktop icon is dead (but I know it isn't because I see a momentary cursor change). Each time I waited several minutes to make sure it wasn't busy installing the updates, including looking at the Task Managers for processes.
Have this been observed by others?