We have the same issues on our UE4 project since updating from UE4.15.3 to 4.16.1 However the delta actually is taken into account e.g. when setting a spinbox to min 0, max 300 range and using a delta of 50 the spinbox slider will jump from 0 to 50 to 100 to 150… but the value by the mouse input is not incrementing according to the delta stepping. Dunno which value is actually returned when releasing the mouse/slider.