Using a custom Resource Pack, darker Grass side and leaves blocks colors textures turn super bright

DESCRIPTION: Whenever using a resourcepack with darker parts on the grass_side or leaves blocks textures, on both fancy and fast, the darker parts will vary from being super bright or super dark (pretty much black). On the leaf blocks at least, it's more prevalent on fast graphics as it has more filled space. This doesn't happen using the default resourcepack or when using 1.7.10 or earlier. It can be noticed in resourcepacks with darker parts in the textures, such as A'thery's Ascended or the custom resourcepack I've been working on.

WHAT I EXPECTED TO HAPPEN: The textures to work as they did in 1.7.10 and earlier

WHAT ACTUALLY HAPPENED: the textures didn't work right and was super bright (or almost black) where it shouldn't be

STEPS TO REPRODUCE:
1.) load minecraft version 14w32a or later (1.8 snapshots)
2.) use resourcepack with darker parts on the grass_side, and leaf blocks textures
3.) view leaf blocks and side of grass blocks textures (both fast and fancy graphics)