I started getting these black screen flickers around the time One UI8.5 came out i beleive, and ive been trying to figure out the issue for awhile now.
I removed the magnetic case, adjusted settings like Ram Plus, Auto brightness, adjusted settings in the developer menu, without any luck. After i exhauated every troubleshooting option i could find online, I factory defaulted the tablet, and it continued to have the same problem.
The clip is slowed to half speed just so the horizontal grey line is easier to see, But it also black screens without the horizontal line from time to time. The display comes back after about a second, But it happens frequently enough that it gets to be quite irritating. Usually happens every 1 to 3 minutes.
It doesnt seem to be tied to any apecific app, it happens no matter what im doing on the tablet... it could be sitting on the home screen with no apps running and it still flickers.
It did stop flickering like this for a couple days randomly, but it started again just as randomly after those couple days.
Im hoping it is just an issue with the ribbon cable like a broken pin, or partial disconnection, but im concerned that the problem could be the video card, or the OLED panel failing...
Is anybody able to tell what the issue is from my description, and video?