Depleted soil leading to -> the margin of the leaves start drying -> so they add hormones or manure -> the plant suddenly experience a "multi branching" event at the end.
I tried to "grow" a couple of mango trees in Switzerland on my balcony, but they all died within 1 or 2 years, I think I burnt one with too much fertilizer, another one due to the weather being too dry and one, I am not too sure but I suspected not enough mineral as it took almost 2 years, I hoped it would grow :(
Mangos are sensible to mineral deficiencies.