This is a bug with Unreal Engine that appears when you are forcing anti-aliasing through your graphics card's control panel. Make sure to set anti-aliasing to use "application settings".
For AMD Cards:
- Right-click on your desktop
- Click where it says "AMD VISION Engine Control Center"
- Click on the "Gaming" option
- Click where it says "3D Application Settings"
- Look for where it says "Anti-Aliasing Mode" and set it to "Use application settings"
For NVIDIA Cards:
- Right-click on your desktop
- Click where it says "NIVIDA Control Panel"
- Click Manage 3D Settings
- Click on the Global Settings or for advanced users you can Add ROGame.exe
- Look for where it says "Antialiasing - Mode" and set it to "Application-controlled"