UCS venator pieces not lining up?

hi all, was making my way through the venator (first big build) and found out that the pieces don’t alone like I think they would and don’t look like the instructions? The bridge needs to be connection by 2 pins and they will go into each other but it then leaves a massive hole in the back where I don’t think there is mean to be one. If I don’t leave a gap at the back then the pins don’t line up to where they’re meant to be. Someone give me answers this is puzzling me submitted by ...