Why is everyone so quick to call anything they dont like a bug? It is not a bug. The early war subs really did have high fairing around the cigarette deck. Here is the Grudgeon, a Gar class sub. As you can see the fairings are high around the AA gun.
It wasn't till ~Mid 1943 till they shaved down the rear fairing and put a railing around the back. Gato class subs along with older Salmon Gar Tambor etc class subs eventualy got the upgraded conning towers. Then it looked like this:
Start a career in 1943 and you'll see what i mean. My sub currently has high fairings around the back too and it does hinder AA gun aiming viewing, so I avoid confrontation with enemy aircraft as much as possible. I am playing with realism after all...