Problem with throttle when using the left stick of the xbox one controller to control the throttle

Hello, I use my XB1 controller only for the throttle control - the left stick is axe that can be good for full throttle control and that’s what I do. But I have some problem with that - when I check the white line movement in the control settings I see that when I move the stick the white line moves smoothly with no problem but when I get in the plane and use the left stick to control the throttle , it moves smooth till 40% then stop and I continue to move the stick and it is return to move smoothly from 60%, and this is very annoying, Is someone know how to fix this ?
I tried other plane and I tried other usb cable and nothing helps. thanks.