Adidan,
Usually the taping needs to be done on the iPad mini. On the iPad Air it is faulty replacement screens. I have had 3 in a row sometimes, you can imagine how frustrating that is.
You can put the screen down before adhering and gently push around the edges without cracking the screen to see if there is any one area that triggers it.
Try and put on the old screen if it isn't damaged to much and see if it still is "ghosting".
If you have another iPad Air for testing you can test the replacement screens to see if they "ghost" on another device.