I've done tests with two other controllers, but even the Logitech gamepad and the PS2 controllers both did the same thing.... after configuring properly within the Model2 emu, then going into the "input test" with F2, one stick cancels out the others axis direction!?!?
I even tried "tricking it" by using "Joycur", and mapped keys to the left & right sticks within Model2, then mapped those keys to the matching directions on both sticks, but no dice... same thing happened in the "input test"
. At least you know it's not your controller but something within the game itself.
I know from reading through this forum that there are "more ways to skin a cat" though, maybe there are other ways to correct this glitch within the coding, but I'm still learning myself, and don't know enough yet to help you more... maybe an ".lua" file in the Model2 "scripts" folder to modify the way the inputs are handled, but you'd have to get advice from someone else who understands the coding.
I'm wondering if anyone else out there has come across this issue?
Anyway, sorry I couldn't be more helpful, good luck.
Cheers