Looks like broad mite damage that was done when the fruit was very small. You can google broad mite in citrus and find lots of information on treatment. The problem is mostly cosmetic; but if you leave the fruit too long on the tree, it can cause rot. The treatment has to be done at the flower/new flush stage; and the most common visual symptom of the mite is a crinkling of the leaf edges of new growth; you would need a 10X loupe to see them and look at the underside of the leaf.

I think that is the problem since some of the leaves did crumple. Thank you and I'll make sure to treat next year.

Are your trees in pots? I ask because if they are in ground you should remove all grass from under the tree to the drip line.

I second the grass suggestion. Grass gives off gas that is bad for the tree.

i doubt this is causing your problem, but maybe. The off orange is low to the ground.

I suspect it's citrus russet mite. Turns skin brownish. Broad mite damage is slightly different.

Broad mite? Russet mite? Rust mite? Practically speaking it is a distinction without a difference. They have the same symptoms relative to leaf distortion; they attack the same plants and cause the same damage; come out at the same time and same conditions; the treatment is the same for all of them; and my untrained eye can't see much difference.

I sprayed my trees over the weekend with Oberon (same as Forbid - that you can actually buy on Amazon. It is a professional product but Bayer has no control over third party sellers.)

its an awesome miticide and will knock all mites out! Although, it is VERY expensive.