The bug: 

Strange green fields in the taiga biome. 

For some reason, some grams in the taiga biome are light green in color.

~Attention: No! It's not a microbiome, it's the taiga biome itself, but with a different color.

How to produce:

Create a new world with this seed:

SEED: 4486349547273827881

Do:

/tp 1423 170 -403