Damir-san
Nice to meet you. Thank you.
When the grafting goes well, a green wood grows up, and a leaf rarely falls. In this sense, leaf dropping concerns me. When the grafting does not goes well, growth of the green wood stops, and a scion dries up by the transpiration of the leaf. I think that in order to avoid dying, a scion spontaneously drops leafs. Thus leaf dropping indicates that the grafting does not goes well.
Sometimes a green wood continues growing with dropping minor leafs. I think that the scion drops the leaf which does not fit environment. In this case, I do not mind leaf dropping.