Green terracotta is supposed to have it's own map color separate from the other green dyed blocks like every other dyed terracotta has. However, it has the same color on the map as any other green dyed block. This makes getting the map color literally impossible to get because green terracotta is supposed to be the only block with that color on the map.

On the attached image, green concrete is top left, green terracotta is top right, lime concrete is bottom left, and lime terracotta is bottom right.