The #passover Lamb is to be killed "between the evenings" on Nisan 14. Tradition says this is between noon and sunset, but the literal meaning is uncertain. It could be taken to mean at twilight or at any time on the 14th day of the month. The ancient rabbis weren't united on what that phrase means. It's ambiguous, even to ancient Hebrew speakers.

Is the Passover First Fruits offering supposed to be on the day after the first high sabbath of Unleavened Bread of after the first weekly Sabbath of Unleavened Bread? Once again, the texts are ambiguous.

The Biblical feast days have lots of stuff for people to fight over if they want to. God purposely left many things in #torah ambiguous. Sometimes a statement might contain multiple meanings or it could just be an opportunity for growth by working out our differences. I recommend that you simply choose not to give into the temptation to argue. Pray, study, and if you are still uncertain, err on the side of unity.