I understand your question now and I am not an expert on this sort of thing. I tried the steps you listed and was able to reproduce the same type of behavior. Perhaps it is a bug or perhaps it is due to the fact (at least in my case) that the title block is tied to another 'intelligent' element - the drawing border.
However, after reading your example, I would like to offer a lateral approach. Are you aware that you can specify both project and sheet content in the title blocks? The copyright date sounds like something you want to be able to change on project basis (although I know that you might also just want the year 2008 symbol). In my title blocks I have a lot of data that is Project specific and other data that is Sheet specific. If you've not done this before: any fields you create in the Title Block Record with the prefix "P_" are go to the project tab, "S_" to Sheet and there is a third division I don't use and therefore forgot.
On the flip side, I can still see the original behavior of not updating after editing the symbol frustrating. Put what clues me in to the object's uniqueness is that trying to right-click and edit on the titleblock when work on the drawing opens the data window and not the symbol.
Sorry I couldn't be of more help.