Retina Display is Flickering Randomly

Over the past couple of months. I have noticed that the internal retina display of my 2013 MacBook Pro 13” has started to flicker. The screen has been replaced completely around 15 months ago and I have not noticed any problems until the past couple of months. When I first noticed the issue, the flickering would happen but if I tap on the screen a little or shake the laptop (shut the lid quickly), the issue would disappear. However, the flickering issue is increasing to the point where it is almost becoming not usable.

Now whenever the flickering is not happening, the MacBook is completely fine. It functions normally and it has absolutely no issues. But the flickering is happening at weird times and I cannot really figure out what is the issue. Now I have some experience with computers and I have opened up the MacBook and checked the connection. The connection appears to be solid and I do not see any wires exposed and/or damaged.

When I plug it to an external monitor, the output picture is perfect. So that is why I am suspecting that it is not a graphics card related issue, but it could be, not really sure.

I have attached some pictures of what exactly happens to the screen. Oh, one more thing, following the flickering, I notice that the screen does not completely go back to normal. I have observed multiple times that there are faint grey horizontal lines that appear on the entire screen. Sometimes these lines show up even before the flickering happens.

If anyone can help me out, that would be much appreciated. I really try to take care of my Mac. I do not use it often but when I do, I hate seeing that this is happening to a screen that is practically still new. I have tried the SMC and the PRAM and NVRAM resets and none of them changed the situation. It is also running the latest OS. The thermal paste has been replaced and the entire logic board has been dusted off last month!