I am misunderstanding the simple fact about the daf. How is Beit Din literally seated on Rosh Hashana at all? Is the reference to the intangible "Beit Din shel Malia?"
H. David Levine, Roanoke, VA
The reference (regarding Rosh Hashanah, as opposed to Yovel) is to Beis Din meeting together to Daven and blow Shofar, because this is how Chazal understood it was permitted to blow Shofar. The Gemara cannot mean that they actually sat in judgment, as they were not even allowed to do so on Erev Shabbos or Erev Yom Tov (see Sanhedrin 32a).
All the best,
Yaakov Montrose