In 1130, when his elder brother MINAMOTO no Mitsunobu, accused of the Toran-jiken (Brawling Incident), was sentenced to the deportation to Tosa Province, Mitsuyasu's involvement was also implicated and he was removed from the post of Hyoe-fu; however, before long, he was reappointed to the former position.
大治(日本)5年（1130年）、闘乱事件の罪により兄源光信の土佐国配流が決定すると、光保もこれに連座して兵衛府の任を解かれたが間もなく還任される。