Double-confirmed... it's the panel.
I just ripped the laptop apart (with no damage to plastic parts by using big zipties as prying tools). I got the protective cover off the panel and I can reproduce the issue by applying physical pressure to the bottom centre of the panel. (See pic)
Edit: Tugging on the wire makes a different type of corruption on the display (more like what would happen if you had a messed up VGA cable).