I have several different smaller mango trees I am trying to grow.
Some of them have no burn and some have issues similar to you.
I give all the mangos the exact same water and fertilizer. I have had
some issues where the leaves don't completely form. I hit my trees
with a pesticide to kill the Sri Lankan weevils and started hitting the
trees with copper fungicide and the trees with issues are responding
and having more normal growth. The trees that had issues seem to
get worse in July and August when it is the most humid.
I am not sure if I have the same issues as you. I have been giving my mangos
Diamond R 8-4-8 granular fertilizer with micros and the leaves are very
dark green. I fertilize once a month a small amount.