have seen it happen to some of our juju branches too. It does not affect our trees much since they are more mature and bigger than yours, so understand your qualms. Where we're at, iron deficiency is often the main culprit. A soil test is best. Probably more reliable to sample native soil at the edge of the compost mound, and not the compost mound you've planted the tree on.
we practice bokashi composting here in vegas-- from vegie scraps, to fish gills, dead pigeons, you name it-- it will be tossed or buried around our yard. Better the scraps serve some purpose instead of letting them rot and stink in the dumpster. Among plant-based refuse, orange/grapefruit peel, cauliflower stalks, spinach scraps, etc are relatively mineral-rich.
this practice(which would make any HOA cringe)seem to be offsetting any iron or maybe magnesium deficiency, especially animal-based refuse.