Could be bacterial, could be fungal, and it could very well be the fact that they've had their entire bodies removed below them.
It's always a crap shoot when cuttings do things; it can either be natural, and figs can and will drop their leaves and go dormant if they're in distress.. But it could also be caused by a variety of things like a lack of sunlight and daily watering without proper desiccation.
I've grown edible figs in water, and they tended to drop all foliage before growing roots and leafing out again. But they were in full sunlight.
Dig them up, see if there's any callus forming or if the bottoms have gone mushy. If the latter is the case, toss them because they will just continue to rot.
Also check for rolly pollies or whatever wood lice are called in Texas, they love eating damaged fig bark. My last edible fig was frozen to death this winter, and the wood lice burrowed underneath the bark before it even looked dead.