Strange Undo (CMD+Z) bug using Intuos Pro tablet

[D.T. Nethery]

About 99% of the time I'm working on my Cintiq.

However, today I needed to work away from home using my old Macbook Pro (running MacOS 10.14.6 Mojave) and my Intuos Pro tablet and grip pen. I'm using TVPaint 11.7.2.

Here is a strange thing I noticed: I have my Intuous grip pen buttons set to Upper Button = Undo (CMD+Z) and Lower Button = Right-Click (the same settings as my pen for my Cintiq).
When I click the upper pen button to Undo , it activates the Move/Pan Canvas mode (as if I had pressed and held the ALT key) instead of Undo. I can't get back to drawing mode until I press the FN key on my Macbook keyboard, so then drawing mode is back to normal. I never had this issue before using the same Intuos Pro tablet and pen on the same Macbook Pro. So I was thinking it may be a bug in TVPaint 11.7.2 ? The workaround/fix was easy: I changed the pen button setting from CMD+Z to U (TVPaint's default Undo) . But it seems strange that setting the pen button to CMD+Z for Undo would seem to activate the ALT key ?