Owners of Galaxy S22 Ultra has revealed this issue with their smartphones on Reddit. They wrote in their posts they saw horizontal pixelated line when they ran videos and games in QHD mode. This line did not appear when viewed contents on their smartphones.
Some users wrote that the line disappeared when they switched Galaxy S22 from QHD to FHD mode.
I exact cause of the issue still not care. Whether it an hardware or software issue.
Sammobile opined that it could be a software issue because changing from FHD to QHD fixed the issue. They expected a software fix soon.
9TO5GOOGLE suggested it could be a hardware issue.