Grass seems to be either the color of snowy plains biome or jungle biome. The color briefly changes if a block is hit on the area, but it changes back afterwards.
Environment
Found this on at least plains, snowy plains and savanna, plus superflat.
MC-299720
Grass chunks are in different colors like a chessboard
Resolved
Invalid
0
This is a known OptiFine bug. Turning off Dynamic Lightning should fix the issue. Please note that the Bug Tracker is only for Vanilla Minecraft bugs, not third-party ones.