TT #221 · Parshas Tazria · Aliyah 5 · Passuk 39
English: the priest shall examine them. If the spots are dull white, it is a harmless bohak that has appeared in the skin; he is clean.
Chabad.org — Chumash, English translation + Rashi for Vayikra 13:39
Torah Temimah cites Sifra (Toras Kohanim) for preventing bohak’s pure status from transferring to a separate baheret.
Sifra — Vayikra 13, Midrash Sefer
English: Could the pure status of bohak also make a baheres that emerges from it pure? The word “it” limits the ruling to the bohak itself.
Textual derivation
A baheret that emerges from a bohak must be judged on its own; the bohak’s pure status does not protect it.