No vertical information on upper left pads

[Phelios]

Hi there,
I got a Push3 and noticed, that the four pads in the upper left corner do not react on vertical information. I am pretty sure, that I troubleshooted the situation correctly by using Ableton's instruments and mapping parameters to the vertical slide height. It works on all other pads, except for the four in the upper left corner.
Question: is there any way to calibrate / repair this problem on my end? Opening a support ticket and sending it back would be my next option. But if I can fix it here quickly, I would love to give it a try.
Thanks!

[[jur]]

1st you should check if midi is sent from sliding those pads, with an app like Midi Monitor, Showmidi (i.e at the OS level, not in Live) etc...
But you should contact Support anyway, that's not a common issue and we have to know if this is a hardware problem.