Some of my oranges are split with a soft black spot and thin skin

Question

The fruit looks dry.

Answer 1

It sounds like the tree has a problem or two. Read these two articles for solutions to the black spots and thin skins.
https://www.gardeningknowhow.com/edible/fruits/citrus/citrus-alternaria-rot.htm
https://www.gardeningknowhow.com/edible/fruits/oranges/oranges-splitting.htm

I'm reading that dry fruit is often due to a tree just being immature. Dry fruit may happen for the first harvest or two, and diminish as the tree grows strong and mature.
This article may also be helpful:
https://edis.ifas.ufl.edu/hs141