Besides your point, the only other downside is that the red line is in the navigation bar, not directly below it. If it's a pixel or two tall it's probably fine

Besides your point, the only other downside is that the red line is in the navigation bar, not directly below it. If it's a pixel or two tall it's probably fine but if it's 4+ pixels tall it'd probably make the vertical spacing of elements in the nav bar (titles, buttons) appear slightly misaligned.