Water rendered differently per eye in Underdark Overbright & Copper

[codeflorist]

Using the Re-Release add-on "Underdark Overbright & Copper", water seems to be rendered differently per eye. The texture seems different and have more contrast in the left eye.

Water can be found right at the beginning by walking to the end of the hallway from the start position, then right up the stairs following the 180° turn and then riding the elevator down.

Copper uses alpha textures, so this may be related to alpha textures or alphatest textures.

Any help pointing to a fix or a pull request is much appreciated!

The problem can be alleviated a bit by setting r_wateralpha "0"