I can't believe you are all missing the obvious:
Bunker A is perfectly matched by the overcast sky and cool winds off the water, while Bunker B blends beautifully with a sunny, dappled sky and warm summer breeze.
Since in both locations these are the prevailing atmospheric conditions, it is obvious that the architects matched the bunker style to the conditions.
It makes perfect sense: if the wind is cold and the sky is grey, I want a rugged, natural scar of a bunker to play out of -- nothing manicured or pretty; while if I'm in shorts and a polo shirt and wearing sunglasses, I want to be in a bunker that looks as good and as stylish as I do!
These modern-day architects think of everything, I tell you...