Steps to reproduce...
1. Start a New Game with the Abdel pre-generated character.
2. As soon as you appear outside the Inn, click the Map icon to reveal the Area Map.
3. Click the World Map icon to reveal the World Map.
The Discovered location of Candlekeep is a faint pixellated grey.
The Undiscovered locations of Friendly Arm Inn and Beregost are a faint pixellated brown.
Both types of locations should be drawn correctly at full opacity.
Exiting and reloading does not correct the issue.
The game version is 1.3.2053 and no mods are used but I do have some custom images in the .local/share/Baldur's Gate - Enhanced Edition/portraits folder.
I am using Linux Mint 17.3 Cinnamon on kernel 3.19.0-42 with nvidia-352 (352.63 drivers.
Hardware specs are Intel i7 4770K at 4.4GHz, nVidia 780ti 3Gb, 32Gb 1600 DDR3, Samsung 840PRO 256GB SSD, Apple Cinema Display 27" at 2560x1440.