Certified GKH Gardening Expert
From the photo, I see two color patterns that I can comment on, none that are of great concern.
The lighter green, yellow appearance on the new growth is normal. Nitrogen will move into the new growth from the older green growth as the foliage matures.
The severe discoloration patterning in some of the older leaves may be due to a nutritional deficiency, a genetic disorder, or a plant disease. It's hard to differentiate without a laboratory analysis.
But since its only a few leaves at this time, I would concentrate on keeping the plant as healthy as possible with good soil and water management. It may outgrow and resist the disorder.
Water is of course the first consideration, not too much or too little:
Fertilize with a complete organic fertilizer formulated for citrus, like this: