Tosefta for Horayot 17:10

[The court] is not liable [to bring a bull as an unwitting sin-offering for issuing a ruling regarding] a positive commandment or a negative commandment that [is related to the defiling of] the Temple, and one does not bring a provisional guilt-offering for a positive commandment or for a negative commandment [related to the defiling of] the Temple (Hor. 2:4). But [the court] is liable to bring a provisional guilt offering for a positive commandment or for a negative commandment regarding a niddah, said Rabbi Shimon. Why does liability that incurs [for a ruling regarding] a positive commandment involving a niddah? Because there is within it a negative commandment. Moreover, Rabbi Yehuda would say over a general rule regarding them: When an individual must bring a provisional guilt offering, the nasi (leader or prince) must do so as well, and the anointed [priest] and the court are exempt (Hor. 9a:10). [But when it comes to] a definite guilt offering, the nasi and the anointed [priest] are liable, and the court is exempt (ibid.).