To really complicate things, fig trees could throw mutated branches or sports just like other plants do. I had a very large Meyer lemon tree that would produce a branch of Buddah Hand lemons every few years. These branches were not suckers but appeared on the North side of the tree several times during 30 years.
I read an old article about how to produce rose sports by manipulating partly mature nodes on roses. My point is that it shows by manipulating nodes and buds we can cause mutations. Maybe disturbing or damage to an undeveloped node or bud is how Panachee occcured, and why some branches will revert.
Rose Lover's Guide, Roland A Brown. pg 193
"Take partly developed buds from far down on canes, near the base of the plant. Graft to suitable rootstock. A large proportion of plants will bare flowers dramatically different from the parent bush."