Reference for Chullin 164:31

אילימא בזה אחר זה ובשתי התראות תנינא

Should you say it is the Rabbis who differ with Symmachos, but surely, if in that case [in our Mishnah] where there are separate prohibitions the Rabbis exempt [the wrongdoer from an additional penalty], how much more so in this case.

Jastrow