It is absolutely normal that the BF-maps can't be zoomed. They are automatic random-generated, so there arn't automap-files for this maps in the different resolutions.
It isn't a Bug. <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" />
The automap bugs with the Battlefields extend way further than just the zoomable maps. Half the time you don't see all of what you've already cleared until you go back.