Black/Flickering bar at bottom of laptop screen?

Unsure what this could be and it was intermittently happening a few months ago. It stopped so I didn't worry about it but it's been happening more frequently. I've looked up solutions but I'm not sure what it can be. I've opened my laptop up and disconnected and reconnected the display cord already which doesn't really fix it (or at least, not for long). I've updated both my drivers and Windows, thinking this would help but it did not. I also changed my refresh rate from 60hz to 40hz which seemed to help months ago but doesn't necessarily help anymore. I also went to my bios where it the black bar was still there.

I've bought both a replacement LCD screen and a new display cable to put in my laptop. My plan was to initially swap out the cable to see if this would help and if not, replace my screen. However, I just turned my laptop on and it's not showing the black/flickering bar anymore? I'm not sure what's happening and don't want to open it up if it's ok right now. At the time when I had the black/flickering bar, I would open up a game and it would somehow stabilize and it wouldn't flicker. I'm not sure what this means. Does anyone have possible insight on this?

For specs: Asus TUF Gaming FX505DT Added Acer 8gb DDR4 ram Added 500gb HD from another previous laptop which I reformatted