2
The ID's for news posts shouldn't shift in order to 'fill up holes' in the database, so the fact that it doesn't do that, isn't a bug. The reason for this is that links are made to that news post, and they should be as static as possible, to keep them current. Also, 'holes' do not exist in the database, it is just that one field (the news item ID), isn't çomplete' anymore.
As for the change of poster to guest, what did you do to change the news post? Exactly, so we can see if it is a bug or not.
Herko