Hi there. I can repeat this at will on my OSX Flash CS5 installation.
Create a few scenes and populate them with content, including graphic symbols.
Double click a graphic symbol in any scene other than the first one.
Perform edit. Click back to scene.
I always end up back at the start of Scene 1.
i get the same issue on pc with cs5 (i believe its always acted that way in previous versions?) - i think Adobe would call it a feature rather than a bug...