As we know, since rejoining with Raava, Korra is the beginning of a new avatar cycle. However, Is Korra no longer a incarnation of Aang and all the other past avatars now that her connection to them is severed. Aang’s spirit was reborn into her. Does her broken connection change that fact.
Korra is still the reincarnation of Aang, the connection between the is simply severed. She was already born before she was unfused, so the spirit that resides inside her, was already (previously) Aang's.
Unfusing and refusing with Ravah did not suddenly kill her spirit and give her a new one.