Buttons within scroll rect are difficult to press on mobile

I have a scroll rect which presents a grid of icon buttons. On desktop the buttons are easy to click, on mobile (android) the buttons are difficult to press. When I tap them It seems that only the hover event is raised (they glow a bit) but my handlers are not invoked. If I smash my fingers into the button eventually I will raise the press event.

Has anyone else run into this ?