From: Rabbi Moshe Sofer
To: Rabbi Refael Gloga
The Chasam Sofer agrees that the Dagul MeRevavah's davar sheyesh lo matirin reasoning is flawed, but fully upholds the Mechaber's ruling that milah shelo bizmanah cannot override Yom Tov Sheini. Drawing on the Mishnah and the Gemara in Beitzah regarding Rabban Yochanan ben Zakkai's enactment, he demonstrates that all Amoraim concur that YT2 is not pushed aside by milah shelo bizmanah, even in a doubtful case of a child born bein hashmashos, and that the Rosh's strict view is better supported by the sources than the Rambam's permissive position.
Source: Shu"t Chasam Sofer YD §252