Could still be a case of hermaphroditism. An undetected nanner could easily dust the whole branch. So you probably made some S1s or an unintentional fem cross with a neighbour plant. There are not many other explanations available I guess.
If that is the case, it would have contaminated my whole grow, which did not happened.
Wouldn't you say that it's impossible for nanner pollen to limit itself only on the two pollinated branches?