What is the cause of this type of video-distortion on a MacBook Pro 2012 (820-3115)?

[captainmac]

What is the cause of this type of video-distortion on a MacBook Pro mid 2012 (820-3115)?
Haven't had it in yet, but customer is sending me this via mail, this is after a keyboard-connector replacement from 2 months ago.
Also, customer reports issues with battery, computer cant run on battery alone, might be unrelated (just a bad battery) but thought to mention it anyway.

Anyone have a clue what this might be just by looking at this picture? (i'm trying to be as prepared as i can for when it comes back to me)

 

[captainmac]

Alright, great and thanks for the insight! It’s gonna come in anyway, told her to hop by already. It’s not a mail in repair.
Might also sell a battery in the process. Thanks again!