Internal Breakdown: This is a fruit problem of unknown cause, which is also called jelly seed and soft nose. Generally, it is less of a problem on the calcareous (limestone) soils found in south Miami-Dade County and more common on acid sandy soils with low calcium content. The degree of severity may vary from one season to another. Several symptoms may appear including (1) a softening (breakdown) and water soaking of the fruit flesh at the distal end while the flesh around the shoulders remains unripe, (2) an open cavity in the pulp at the stem end, (3) over-ripe flesh next to the seed surrounded by relatively firm flesh, or (4) areas of varying size in the flesh appearing spongy with a grayish-black color. This disorder is aggravated by over fertilization with nitrogen. If fruit have this problem, reduce the rate of nitrogen. In sandy and low- pH soils, increased calcium fertilization may help alleviate this problem. Fruits harvested mature-green are less affected than those allowed to ripen on the tree.
From the following IFAS page:http://edis.ifas.ufl.edu/mg216