Stage Light Effect on MBP 2020, possible to repair?

The first generation of the thinner MacBook Pro's in 2016 had a fatal flaw! The new ribbon cable design used in the displays connections was a finicky beast! Which is the start of the stage light affair! Here in the 2016/17 models thicker backlight cable lines was a bit stiffer than the thinner line signal line cable so if bent was less flexible. This became an issue at the apex of the bend when you lift up the lid. At this midway point the lift stress on the cable and the space it needs to flex is limited by the mechanics and the space the engineer allotted. The length of the cable then becomes critical as being too short or too long can lead to failure! The issue here was the thicker lines Vs the thinner lines as they failed to test or failed to understand how it was different. So the cables lines cracked! And a few different patterns of stage light or even a full failure could happen. The solution was simple! Lengthen the cable about 10mm! Apple was quaking as the cost of such a recall and the complexity of replacing the cable was immense! They dragged their feet as long as they could in the mean time a second major defect surfaced with the much bragged about Butterfly keyboard as it too was failing, and even a third failure in this new design was the lack of cooling for the Intel CPU chip Apple had to use as Intel was not able to deliver the promised cooler running chip!

Apple did learn its lessons!

• Longer display cables ✔️
• Back to the better older keyboard ✔️
• Jumped to a much cooler chip (theirs) ✔️

Sadly, the environment hit them with one more!

The sand and grit in the air would collect in the cables cavity sticking to the surfaces the cable would rub so over time the insulation of the ribbon cable would wear exposing the copper traces inside. This is where the distances between the traces and the current the trace needed to carry became a factor as well as the areas the cable would rub. This at least can be fixed if not too severe. Otherwise it requires a new cable which is extremely hard to do as cracking open the display assembly is not easy without leaving it damaged a bit and it would be as stable as the original. Which makes a full replacement the better but costly!

So if you live in a sandy or gritty environment (very arid or near a beach) you may need to pop off the bottom cover a few times to clean out the dust and sand/grit so prevent damage yearly.

And we still had one more!

Here it was mostly user created! Here leaving a paperclip or other object near the hinge area can crack the glass chin plate so the glass shard then presses into the ribbon cables just behind cutting it when the lid is closed! Or, a snap-on case cover is used which the holding tabs hit the chin plate area doing the same thing! Apple sorta fixed this going to a plastic chin plate.

These last ones are not very common!

I know a very long story!

So... what is your issue here? Environment sand or grit, or a cracked Chin plate cutting into the ribbon cable?

Time to pop off the bottom cover to inspect things and try cleaning using a soft long bristle brush to sneak under the ribbon cables without creasing them to try to scrape off the grit and sand, then using a few short blasts of can'ed air or compressed air if you have a clean oilless compressor. Follow this guide MacBook Pro 13インチ Two Thunderbolt Ports Late 2020 ディスプレイアセンブリの交換 to Step 14 so the system is not powered. You may need to get down to Step 30 so you can visually see the damage if you are lucky a more detailed clean and a thick paint over urethane based sealer might save things if the traces aren't damaged.