Grass is the wrong color after exiting the nether

When exiting a nether portal in a cool biome such as extreme hills or taiga, the grass blocks will randomly be very green in spots, as if you are in a forest biome. This doesn't seem to happen unless you use a portal to get there, however. If you update these spots, however, they will turn to their normal color.

Note that this occurred with biome blend turned off and has not been tested with biome blend on.