As of Polytone 2.2.0, and persisting through 2.2.1 and 2.2.0, legacy colormaps in Optifine's Grid format seem to be starting at Biome ID 1, not Biome ID 0. This means that all biomes are shifted one pixel left on the grid, rendering all of them incorrectly and breaking any pack that uses Grid colormaps for grass.
I.e. Meadow, which is numeric ID 29, now corresponds to the pixel at position 28 (previously corresponding to Wooded Badlands), not 29, making Meadow grasses brown. Similarly, Plains, which is numeric ID 1, now corresponds to the pixel at position 0 (previously corresponding to The Void), not 1, making Plains grasses bluer.