Kishi will probably reveal it later in the future, like he probably will with hagoromos brother.
Kishi cleared up(mostly) the origins of the byakugan. Something that was very minor to the plot. I do not think he will leave major loose ends.
The cycle of NB.
OHHH WTF that is a major plothole. Kishi made a mistake. He never explains anything.
several, or many chapters later
Ohh kishi had that planned from way back then. It makes sense now.
or
Ehh i dont buy it, but at least it was explained
It is just kishis style. Leave a piece of the plot hanging, to build up tension, and then reveal it, and repeat.