Interesting to me to see that Soursop flowers in Fall but fruit development did not occur until the early spring, I thought most were duds, out of 17 developing sops on tree #1 I have found only one sop with bacterial spotting, I was alerted by a black beetle attempting to burrow into damaged area, I did see some small fly larvae in wound also, I’ve read online that bacteria/fungi develop on rotting twigs, or leaves then drip onto fruit, removal of dead debris advisable and may be of value to have an open spreading canopy with lots of airflow