Sforno on Numbers 30:16/ספורנו על במדבר ל׳:ט״ז

1ואם הפר יפר אותם אחרי שמעו, more than 24 hours after he had heard about it, i.e. when the period during which he could have cancelled it had expired, he can no longer change his mind;

2ונשא את עונה, the same guilt as that of a person who forces someone else to commit a violation of Torah law, or who teaches Torah other than according to the halachah, thereby misleading the student.