Grass block and leaves sides are not colored correctly in first person mode when being held in the hand

Important: This ticket is only about the sides of those blocks being not quite the correct color. The top of grass blocks and leaves being gray is MC-161837.

The bug

The sides of grass blocks and leaves seem to be incorrectly colored in first-person mode when held in the hand. It seems like the colors are have less saturation than they should have.