These symptoms are likely abiotic (environmental, not pest- or disease-caused) and as such would be not very concerning this relatively late in the season (even if it began a month ago). Has the plant been checked for water regularly in periods with sporadic rainfall? (Similarly, is it being allowed to dry out between waterings?) Figs have decent drought tolerance but aren't fond of consistently damp soils. Cumulative and varied environmental stresses throughout the growing season can cause shrubs and trees to begin the leaf-shedding process early. Complicating things, sometimes leaf-decay fungi can colonize such senescing (in the process of shedding) leaves, making it appear that an infection was the cause. Spotting like what we see here could be due to that or simple chlorophyll breakdown as is normal during senescence.

If the plant is so dense that it's shading much of its own growth or has poor air circulation against the house wall, you could consider trimming some of this growth back or thinning-out dense stems next spring. As you may already be aware given the age of your plant, most fig varieties when mature in our area can easily reach at least six to eight feet in height and width, so they need a good amount of "breathing room" to thrive. Although a building wall can give them good protection as a temperature and wind buffer in winter, giving them enough distance from it can help with overall vigor and leaf retention.

Miri