I'll have to find my pix, but I have seen the second style on a few occasions, but this is the first time I have seen the fig grow a stem from the first fig. Usually the second one develops as an extension of the first one, and you just see a scar line, which I think is caused by the edge of the eye, when the second fig grows out through the eye of the first.
I have no idea of the cause, but I know they have seen the second style at Davis, as well, in the past.
I am sure it is just a "fluke". You seen deformities and miscarriages throughout the plant animal world. They are infrequent, but some very bizarre things do occur every one in a while.