It seems that the devs created a area underneath the buttons that does not interact with blocks (break or place).
This is what allows you to move instead of just placing or breaking a block behind the button.
However, it seems that this "no input zone" does not scale with the size of the device screen.
To solve this problem, I found that using button size 40 or lower on Ipad Air 2 will fix the problem completely. I do not know about other devices.
Saarthd123
It seems that the devs created a area underneath the buttons that does not interact with blocks (break or place).
This is what allows you to move instead of just placing or breaking a block behind the button.
However, it seems that this "no input zone" does not scale with the size of the device screen.
To solve this problem, I found that using button size 40 or lower on Ipad Air 2 will fix the problem completely. I do not know about other devices.