Ok I figured out what the actual problem is.
I first set my zoom key to Key1 (that's how XP11 recognizes it) and speedbrakes to Key2.
However sometimes I notice Zoom doesn't work, so when I check the keyboard Settings I see that Zoom is now on Key2 and speedbrakes on Key1.
Somehow, XP11 is switching Key1 with Key2.
Thank you for helping!