Sunny did not miss the fact that neither Ravenheart nor her daughter had seemed to possess the lineage in the early years of the Nightmare Spell era. At the Academy, Orum had noted that Smile of Heaven and Anvil were exhibiting unexplainable physical prowess and strength… but Ki Song was not.
That was because by then, Immortal Flame had already claimed the Lineage Memory of Sun God, while Warden of Valor had already found the Lineage Memory of War God. Nightwalker, meanwhile, had most likely already gained the Lineage Memory of Storm God.
Sunny did not know how Ki Song earned the Lineage Memory of her own or where, but she definitely had not inherited a divine bloodline, like Smile of Heaven and Anvil did. Instead, she found it at some point after Awakening, just like their parents had.
Then, she followed Broken Sword into the Third Nightmare and attained Sainthood. By then, Clan Song would have already been considered one of the Great Clans.