what's this?

this is a demo of a bug i found in my thinkpad x270's display (a 12.5" FHD IPS panel - CMN model 1239 manufactured in year 2015 week 6, according to edid info.)

the entire left hand side of the screen is a uniform dark grey (take a screenshot and crop out the right hand side if you don't believe me). however, on my display, there is a light grey stripe at the same vertical position as the red stripe on the right hand side of the screen. (here's what it looks like on my screen)

if you have any idea what causes this, please let me know! Some people have speculated on lobste.rs