This is definitely a thermal/load issue. I’ve been having the lines at the bottom of the screen everyday after I use my MBP 15” mid 2016 after a few minutes. I used to be a power user with a lot of heavy apps and tabs open in the background all at the same time and I only put my laptop to sleep by closing the lid and never shut it off completely. The fan of the laptop always spins up to the max most of the time I use it. Then I tried shutting it off and closing unused background apps and turning off the machine during the weekend when I’m no longer using it. I also opened the back cover of the laptop to see that the vents and fans have a lot of dust build up making the laptop not cool down efficiently. Now the lines are no longer appearing unless I push the laptop to the max again for an extended amount of time making it run hot. I think this is definitely a hardware defect in the screen where the screen is overheating creating the lines and maybe the diffuser is getting delaminated which is a shame. But...

Happening on my MacBook 15” Retina mid 2016 and when i stopped using it for a few weeks when i went on vacation, when i returned the problem did not appear for a few days. Then it came back again after I used the computer heavily and has not stopped happening since. I think its related to thermals and appears when the computer runs hot. I hope Apple acknowledges this problem and creates a service/recall or extended warranty program. They need to know that there are already a lot of units affected. This is also happing on my 2 friends MBPs - a Retina 13” and a 15”.