Rashi (DH "ha'Motzi") says that the case of Takfa Kohen is when the Yisrael was originally quiet when the Kohen seized the animal, and only afterwards started protesting this injustice. However, the Ritva explains that the case is even when the Yisrael protested when the animal was seized. The Acharonim understand that Tosfos (DH "vi'Ha Hacha") holds like the Ritva (see, for example, the Pnei Yehoshua and Tiferes Shmuel regarding the logic behind the opinions of Rashi and Tosfos respectively).

All the best,

Yaakov Montrose