I have an S21 Ultra, all of a sudden I am getting a white horizontal line going from the edge of the phone to the left of the camera when I am opening my screen.
I'm not sure if it a setting or if it's telling me something is not quite right. I've rebooted it but still apears.
First try booting to Safe Mode and see if the lines are still there.
Then after a normal boot where the lines are there, please submit an Error Report. Samsung Members app->Get Help->Feedback->Error Reports
Galaxy S21 Ultra 512g(VZW), Galaxy Book (original, VZW), Tab S8 Ultra, Tab S4, Galaxy Watch3(VZW), M8 Smart Monitor