Its fine, your nuts may be a touch to strong, maybe only half? just like anyother plant tree, when its all over & the plant uses what it wants from the fan leafs the leftover sugars make the leafs turn.
Looks like 1 female, 1 male. Also leaves looks really dark. maybe slow down on the fertz. Its weird that the female is sexing but the other is not because males will pre flower about a week or so before a female so maybe both female