If Narada Muni is an incarantion then is he a jiva-tattva or Vishnu-tattva?

From: Dhananjay Vashistha

Narad Muni is the incarnation of Krsna that means he comes in Vishnu Tattva, but in the previous life he was a normal dasi putra i.e. he comes in Jiva Tattva. Please clarify this contradiction.