Board Thread:Theories and Speculation/@comment-3001903-20150829033326/@comment-734582-20150830130707

Seelentau wrote: Ya'll have to consider that Rasa learned the Magnet Release by himself as well, even though it's a Kekkei Genkai. I probably wouldn't take the whole "learned it/taught it" too literally. Given the influences of Tailed Beasts, it's possible that he somehow stole some of Shukaku's power. Alternatively, kekkei Genkai may sometimes manifest clearly (e.g. Ice Release for Zabuzas kid) and sometimes require conditions (e.g. Sharingan/ Himawari's Byakugan) to awaken. Maybe Rasa had Magnet Release all along but was unaware of it/unable to use it until he taught himself.

So all in all, people may be unaware of their Kekkei Genkai (wasn't kakashi unaware of his Mangekyou until Part II?) until they get to a certain point, so it may seem like they "taught" themselves while they actually just awakened it.