It seems that there's some sort of disparity between the visual appearance of the switches and the actual hit boxes thereof, as I had a great deal of difficulty hitting the switches with my Antigua this afternoon despite the shots visually appearing to connect.
I believe the trouble may be caused by the hit box for the closed gates being too large and blocking the sides of the switches from being hit.
Even swords will fail to hit the button, if you stand close to the walls and a little bit too far to the side. You will swing, the button is in the range of your sword (you can see it's the same range where you can hit a monster), the sword will pass right through the button, but button doesn't get triggered.