I'm gonna guess that it's rust from overwatering. Figs are tough and even when they show signs of Fig mosaic virus it is only because they are stressed out in some way. When the stress factor is eliminated, no more fugly leaves :)

You don't have your location or planting zone in your profile. Please put that into the planting zone section. Then it will show like mine, and it will help us to help you. Where I live, rust is not anything that happens. Too dry here. If you get a lot of rain, or you are in a humid area, it's common. I have no clue how to treat it, but if I were you, I would do a google search, "How to treat rust on Fig trees" Good luck

Unless you absolutely must have 100% perfect fig trees, just ignore it. Fig trees will most always correct themselves.

"The most common disease of fig in the southeastern United States is the fig rust (Cerotelium fici).
Fig rust turn leaves brown, can cause defoliation and premature
ripening of the fruit, and decreases cold tolerance. This disease can be
controlled by a 5-5-50 Bordeaux spray (copper sulfate, lime and water)
applied every two to three weeks.

Other fig diseases include Botrytis cinerea (fungus) and Cercospora leaf spot fungus (Cercospora fici), which causes branch terminals to turn black and die. Thread blight (Pellicularia koleroga) results in necrosis of stems and matted foliage. Botryosphaeria dothidea (fungus) causes necrosis of leaves and stems. Rhyzopus stolonifer (smut) causes fruit drop of cultivars with an open eye. Fusarium spp. and Aspergillus niger are fungus that attack ripe fruit."

Thank You all for your input.