right hand 1/3 of screen is darker

i recently replaced the glass/digitizer on an ipad 4 wi-fi model. when putting it back together I noticed that the righthand side of the LCD was darker than the other 2/3. I cleaned the contacts and tried two other known good working LCD screens with the same result.

I am not sure what the issue could be! I have not put the known good working LCDs back into other ipads to see if something happened to them but either way its just not right.

I have spoken with other technicians who have had the same issue and do not have an answer.

Please help