To fix this issue:
- Uncheck any developer options located under Settings, Developer options.
- Return the device to the default wallpaper: Settings, Personalize, Wallpaper, HTC Wallpapers.
- Uninstall the following downloads:
- Third party launchers under Settings, Apps, Downloaded.
- Third party lock screen or home screen widgets by navigating to Settings, Apps, Downloaded.
- Any third-party application where the issue occurs.
- Test if the lines still appear.
- If problems continue, perform a master reset.
- Reinstall applications one at a time to determine the problematic application.