Bought the 2017 June/July kaby lake ntb MacBook...

2017 July MBP nTB Down and up key not working. 40-60% of the time it could not register the click.

Unmodified down and up keys are not generally part of the MacOS interface. What did you expect them to do?

I thought they would have solved the issue for the 2017 kaby lake model...got it 3 days ago and I just discovered this problem while I'm doing my report that requires me to press up and down