Sorry about the issue. Do you see the lines on video footage or still images (like PNG or JPEG files)? Please highlight the source file affected by this issue in the Project Panel > Right-click > Select Media File Properties, and share the details here. Please also share your current Premiere Pro version and OS details.
If you go to the Program monitor, click the wrench icon, select High Quality Playback, does that make the lines go away? Please let me know.