Trying to solve eggplant puzzle

I am trying to figure out what is that going on with my eggplants every year. It starts with a little eggplant be a wrong color. Normally even the very small eggplant fruit have a dark purple color. They grow and color stays same shade. When they overripe, they lose shine, but stay purple. And this is all normal. But from time to time on the same plant where the normal eggplants were growing a baby eggplant appears that looks much lighter then normal and somewhat stripped. As it grows, the color stays light , when overripe it turns somewhat yellowish/brown. And fruit is much harder to squeeze than normal. When cooked I do not see much difference. Any idea on what it could be? Google doesn’t help much as words “eggplant” and “color” and “stripped” gives to much seed selling results…

I have had the same issue of the same eggplant bushes producing two different eggplants. This was a Thai eggplant bush that was supposed to produce, greenish fruit. Once in a while, it produced solid yellow ones. Must be something in its genetics.