Hi there!
Depending on which I’m drawing on (Intuos or Cintiq), the Zadd and Zsub behaviours are reversed.
Everything works fine when I work on my main monitor using my Intuos, but as soon as I move my Zbrush over to my Cintiq Zadd turns into Zsub.
Here is a short video demonstrating the issue:
Tablets:
Wacom Cintiq 13HD
Wacom Intuos pro medium (2017)
Thanks for your help!