Is there a דין of פורס מפה ומקדש on ראש השנה?
i.e. If I eat a meal on Rosh Hashanah by day (first day) do I have to finish eating before shkia?
Answer:
You need to stop to eat at shkiah until you make Kiddush. However, besides the regular reasons why Pores Mapa is not preferred, between two days of Yom Tov there are additional problems, and therefore Pores Mapa should not be done.
הדלקת נרות לפני קידוש וקידוש לפני צאת הכוכבים. וגם חששות מצד דיני הכנה.
וראה כאן:
#23812