Gittin 54B

נפלו ונתפצעו; אחד שוגג, ואחד מזיד ⁠– לא יעלו, דברי רבי מאיר ורבי יהודה. רבי יוסי ורבי שמעון אומרים: בשוגג ⁠– יעלו, במזיד ⁠– לא יעלו.

If there are nuts from Perekh that are orla, and they fell into other nuts and became intermingled with them, the entire mixture is forbidden, even if the nuts that are orla are few in number. This is because they are deemed significant when they are whole and they are not nullified in a mixture. If the nuts were broken afterward, whether they were broken unintentionally or they were broken intentionally, they are not nullified in the mixture, despite the fact that they are no longer regarded as significant and should therefore be subject to nullification; this is the statement of R' Meir and R' Yehuda. R' Yosei and R' Shimon disagree and say: If they were broken unintentionally, they are nullified, but if they were broken intentionally, they are not nullified.

והא הכא, דמדאורייתא חד בתרי בטל, ורבנן הוא דגזור, וקא קניס רבי יהודה! התם היינו טעמא דרבי יהודה, משום דאתי לאיערומי.

The Talmud asks: But here, by Torah law the forbidden substance is nullified if its ratio in the mixture is not more than one in two, i.e., when the majority of the mixture is permitted, and it was the rabbis who decreed that significant items are not subject to nullification. And nevertheless, R' Yehuda penalizes an unintentional offender due to an intentional offender. This seems to contradict what was stated previously, that R' Yehuda does not impose a penalty for an unintentional offense if the transgression involves the violation of a rabbinic law. The Talmud answers: There, this is the reasoning of R' Yehuda, that a penalty was imposed in the case where he unintentionally broke the nuts due to the concern that without a penalty he will come to employ artifice and intentionally break the nuts in order to effect nullification of the Perekh nuts.