Makkot 16B

התם, גברא בר תשלומין הוא, ושיעבודא דגר הוא דקא פקע.

The Talmud answers: There, the man who appropriated the collateral is liable to remit monetary payment, and it is only that the lien of the convert on the property has lapsed, as there is no one to receive payment. Therefore, he is not flogged, based on the principle: One is not both flogged and liable to pay restitution.

והא איכא פאה, דרחמנא אמר ״לא תכלה פאת וגו׳״ ״לעני ולגר תעזב אתם וגו׳״,

The Talmud asks: But isn’t there the case of pe’a, where there is a prohibition, as God states: “You should not wholly reap the corner of your field” (Leviticus 23:22), followed by the mitzva: “To the poor and the convert you should leave them” (Leviticus 23:22)?

דמשכחת לה בקיימו ולא קיימו, ביטלו ולא ביטלו! דתנן: מצות פאה להפריש מן הקמה. לא הפריש מן הקמה ⁠– מפריש מן העומרין. לא הפריש מן העומרין ⁠– מפריש מן הכרי, עד שלא מירח. מירחו ⁠– מעשר ונותן לו!

And you find one liable to receive lashes in those cases both if the criterion is whether he fulfilled the mitzva or did not fulfill the mitzva, and if the criterion is whether he nullified the mitzva or he did not nullify it, as we learned in a baraita: The mitzva of pe’a is to separate it from the standing grain still growing from the ground. If he did not separate it from the standing grain, but reaped the entire field, he separates a portion from the sheaves as pe’a. If he did not separate it from the sheaves, he separates it from the pile where one places the kernels after threshing, before he smooths the pile. Once he smooths the pile, the produce is considered grain from which one is obligated to separate terumot and tithes. If he already smoothed the pile before designating the pe’a, he tithes the grain in the pile and then gives the pe’a to the poor person. Once he grinds the kernels into flour, he no longer separates pe’a.