Screen keyboard behaviour when using Pure Piano

When I am using Pure Piano with Dorico I am getting some odd behaviour when using on screen keyboard. The keys play the notes fine when I press near to the root but doesn’t play or plays with delay when pressed lower down (higher velocity). Is there a way of resolving this? I’m a beginner so this could be a pretty basic error on my part. Thanks.

Is there perhaps a setting in Pure Piano to change its responsiveness to MIDI note on velocity?