It would help telling us which state you are in, fertilizer used, amount of sun, type of soil, etc., before diagnosing it.

oh sorry!
I'm in southern BC Canada :) zone 6
full sun all day, and I've used a general miricle grow fertilizer but it wasn't during a hot period. Our temps right now are about 26-32 C (79-90).

All other sections of the plant seem super healthy so curious to know if this one Branch is plagued with something.

The reason I asked about where you lived is because HLB is really bad in California and Florida. I am not familiar with what you are experiencing so hopefully somebody else can help you.

Looks like it is trying to become variegated; that sort of anomaly is quite common in citrus. The leaves look healthy other than the color variation. I would leave it and see what happens.

Could it be wood pocket? I believe it’s a disorder unique to limes and limb dieback is one of its distinguishing symptoms.

Maybe a bit hard to tell from the photo; but to me the branch doesn't seem to be dying, only changing color; and it is only one small branch. The tree in general looks quite healthy.