Display problem with macbook pro mid 2015
Looks like the connectors to those columns of pixels are coming loose.
I had the same problem with a 2009 model MBP, about 1/2 the size of your problem and not at the very edge but in roughly the same position. It was intermittent at first but got worse over time until that column of pixels stopped displaying properly at all.
Apple would want to replace the top of the macbook. Possibly an electronics repair should could fix the cable instead of replacing the whole display section.