A. It is the common custom not to repeat on the second night what was done on the first.
However, Sefer HaSichot 5704, p. 135 writes: “On the Second day of Shavuot, 5704 my revered father-in-law, the Rebbe, relates that the Ba’al Shem Tov cherished the second day of Shavuot. Every year on the second day he would hold a special feast and linger with his chassidim.
The Maggid of Mezeritch, the Ba’al Shem Tov’s successor, explained the reason for the Ba’al Shem Tov’s behaviour. The second day of Shavuot was the first complete 24-hour day after the Jews received the Torah. The Maggid would add: “In particular, this is true according to the opinion of Rabbi Yossi, (Shabbos 86a) who maintains that the Torah was given on the seventh of Sivan. This is a wondrous dimension.”
On the surface, the two rationales given by the Maggid are contradictory. If the day is so dear because it was the first day after the giving of the Torah, then according to Rabbi Yossi, this dearness should characterize the eighth of Sivan? But if the dearness results from the fact that the Torah was given on that day, then according to the Sages who maintain — as the Alter Rebbe rules in his Shulchan Aruch (494:1) — that the Torah was given on the sixth day, it is the first day of Shavuot which should be cherished.