How to fix background image flickering upon scrolling

Question

So the background image is resizing and busting out of viewport when 'site url' portion moves up and down. The problem is occurring in Chrome Android. Here is a video link of the problem.

https://youtube.com/watch?v=HsxC3Pa1JC4

And I am just using basic styling for image.

body {
  background-image: url('imgurl');
  background-size: cover;
  background-attachment: fixed;
  background-repeat: no-repeat;
  background-position: left;
}

I haven't tried anything yet because I don't know whats the issue exactly.