How to fix the problem of object instantiating partially?

Hi All

Environment: Unity 5.3, Platform: Android, Canvas: Scale with screen size, Reference resolution: 480 x 800, screen match mode: 0.5,

I am creating a top down infinite racing game for android where I am moving the track in y direction infinitely. I am instantiating enemy cars coming in opposite direction from top of the screen after every second. My game works well on 5.5 inch or bigger screen. But I tested it on couple of 5 inch screens and problem there is, When enemy cars instantiate, they appear when they come half of the screen.(so they look like half cut)

It looks like there is an invisible diagonal line on screen and when cars come below that diagonal line they become visible. I am not able to understand where the problem could be.

Please see the screenshot.

https://www.dropbox.com/s/o1rn52a8x1fhhdh/IMG_20160914_190919.jpg?dl=0

Thanks