Above is what I sometimes see when I'm in preview mode.
Here is what I see on my computer screen when I bring up any of my blogs. The navigation bar is clearly missing. Only sometimes does it show up when I'm in preview mode.
Here is an print screen of the Page Elements showing how the NavBar is clearly shorter than the width of the 3 sections below it i.e. left sidebar, body posts & right sidebar. I'm not sure how to resolve this within the Blogger Beta layout template.