When playing maps that require T4M it is recommended to NOT play on "Extra".
You should change the Texture Quality to "Manual" and set the 3 following settings to either Low, Normal, or High, to avoid problems.
- From the menu open OPTIONS & CONTROLS
- Go to TEXTURE SETTINGS
- Set Texture Quality to "Manual"
- Set Texture Resolution, Normal Map Resolution and Specular Resolution to eith Low, Normal, or High.