I know nothing about the development of these games, but speculating based on what I've seen, it doesn't necessarily mean work hasn't started on that scene yet. If you've played enough games, you've probably seen some where only the actual characters are "normal" and all the people in the background are just like mannequins? My presumption (and anyone with actual knowledge can chime in to correct this if wrong) is that you can get a lot of the scene done with these mannequins as "placeholder" models, and then add the "skin" to those mannequins at a later stage, kind of like the game equivalent of storyboarding with very rough drafts so you can see how it all looks, then making your final product based on those storyboards.