Ipad Pro 2018, one vertical line of my screen is acting with different pressure!

When I draw with my apple pencil on Sketching apps, one vertical line (almost on the center of screen) is not responding normally and the sensitivity of that part is different. It force my straigt line to go down or even stop the line ( see attached Illustration, Black line is done with apple pencil, Green line is done with finger, Red line is the vertical line that is acting wierd)

I have tried to force quit, restart, clean my screen. None of these have worked.