Shevuot 12A

שאני קטורת דלא בר רעיה היא!

no proof can be drawn from there, as incense is different, as it is not an entity that can be left to graze. The option that exists for animals to leave them to graze until they develop a blemish and then redeem them obviously cannot apply to incense. Therefore, it is reasonable that with regard to incense, since there is no other way to rectify it, all will concede that the court makes a stipulation.

אלא רבנן דפרה ⁠– דלמא שאני פרה דדמיה יקרין!

Rather, say it is the opinion of the rabbis who ruled, in the baraita cited above, with regard to the red heifer that it may be redeemed if a choicer one is found. The Talmud rejects this claim: Perhaps the case of a red heifer is different, since it is of great monetary value. To avoid a considerable loss, the court makes a stipulation despite it being an uncommon case.

ואלא רבנן ד״אמרו לו״⁠ –

Rather, say it is the opinion of the rabbis that is introduced with the phrase: They said to him, in the Mishnah on 2b.

ממאי דרבי יהודה היא ⁠– והכי קאמר ליה: בשלמא לדידי דאמינא לב בית דין מתנה עליהן ⁠– אמטו להכי יקרבו; אלא לדידך דאמרת לא ⁠– אמאי יקרבו?

The Talmud asks: From where do you know that the tanna referred to as the Rabbis is R' Yehuda and that this is what he is saying to R' Shimon: Granted, according to my opinion, that I say that the court tacitly stipulates concerning offerings that their consecration is contingent upon their eventual use, it is due to this reason that they can be sacrificed on an occasion different from the one they were initially intended for; but according to your opinion, that you say that the court does not make such stipulations, why can they be sacrificed on an occasion different from the one they were initially intended for?