This series had bad solder joints on the T-CON board ribbon connections. Apple was replacing the displays under an extended warranty program, I would press the Apple service center if that program is still available. If not you might find a tech with the skills to re-solder the ribbon cables.
There is also issues with snap on case covers as well as objects sitting on keyboard area near the display so the glass chin plate gets damaged which in turn punches into the ribbon cable damaging them.
The last issue some people have encountered abrasion of the ribbon cables exposing the lines which could short out. Cleaning the exposed ribbons in the hinge area and maybe a thin coat of non-conductive paint after a careful inspection. This is the only repair besides replacing the assembly which you can review here [post|855176]