So I looked at the tub of sunflower lecithin that I bought around July 2021 and it is clear that the color has turned from a much whiter color with hints of yellow to an salted egg yolk-like color with hints of white.
Taste-wise it now tastes normal at first, then immediately turns very sour like I've eaten some sour candy then extremely bitter shortly after.
A fresh batch of sunflower lecithin would taste slightly bitter, but it was very tolerable and no hints our sourness at all.
Odd thing is it hasn't been even 1 year since i've opened it (although not refrigerated and only at room temp) and kept in the pantry cabinet.
Best used by date is still April of next year but it is already inedible for me. My coffee tasted so bad