It could be fruit fly damage. Generally the adult female flies lay egg just under the skin of semi ripen fruits. The maggots develop and feed inside the fruit, causing the flesh to turn brown and soft which emits foul smell. This damage also act as entry site for fungal and bacterial pathogens. After maturation, this maggots fall out and pupate in soil.

Collect the infected/fallen fruits and destroy them. Use traps to monitor fruit flies. Normally traps can be purchased in the market or you can prepare one. Take plastic container with lids (one quarts yogurt container is fine). Drill holes (10 to 16 holes) that are 3/16-inch in diameter around the upper side of the container. Add 1 to 2 inch of pure apple cider vinegar (not flavored one) and a drop of unscented liquid dish washing soap into the container. Hang the container in shade near trees before fruits ripening and check the traps frequently for flies. You have to change the vinegar every week.
Also use of netting or floating row covers around the bush helps in preventing infestation. If infestation is severe you can spray suitable insecticide.