Parashas Metzora · Passuk 15:28
Chabad.org — English translation + Rashi
Torah Temima points to Niddah 37a.
English: “And if she becomes pure from her flux” — from her flux, and not [necessarily only after she is pure] from her flux and her nega, and not from her flux and her childbirth.
Independent counting for zavah
Chazal allow the seven clean days for zivah to begin when the flux stops, without waiting for concurrent recovery from tzaraas or childbirth impurity.