SpinBox nearly unusable on touch-based devices

The SpinBox works quite nice on desktop with a mouse, but on touch-based devices I found the following issues which make it nearly unusable:

1. All styles: If one of the indicator buttons is pressed, the buttons stays pressed and the value keeps increasing resp. decreasing.
2. Universal style: I find it extremly difficult to hit one of the indicator buttons. Standard and material styles are ok.