This is the same native Japanese reading that appears in the phrase 'Yahata-gami' given in "Nihon Ryoiki" (Miraculous Stories from the Japanese Buddhist Tradition, written in the early Heian period) and 'Yahata-no-miya' given in 'Tamakazura' (Jeweled Chaplet) of "The Tale of Genji."
『日本霊異記』の「矢幡（ヤハタ）神」や『源氏物語』玉(タマ)鬘(カズラ)巻の「ヤハタの宮」のように「八幡」は訓読でした。