Shalom Yeshua HaDerekh, Leviticus 23:15 states that the counting STARTS on the morrow AFTER the Sabbath:
Leviticus 23:15 And ye shall count unto you from the morrow after the Sabbath (H7676), from the day that ye brought the sheaf of the wave offering; seven sabbaths shall be complete:
And here is the Sabbath command:
Leviticus 23:3 Six days shall work be done: but the seventh day [is] the Sabbath (H7676) of rest, an holy convocation; ye shall do no work [therein]: it [is] the Sabbath of Yahweh in all your dwellings.
As you can see, both use the Hebrew word (H7676) for the word Sabbath. The count and the weekly Sabbath is the same (H7676). So the Jews count from the morrow after the High Day, not the weekly Sabbath. This year Shavuot is Tuesday, May 30th sunset thru Thursday, June 1st sunset. They always start their count from the morrow after Abib 15, the High Day Sabbath, and not the weekly Sabbath that you count from. The argument here is that you deny that Abib 15 can be a Sabbath, and it is obviously a Sabbath for the Jews to be counting from the morrow after this day for Shavuot (Pentecost).
The Jews are in ERROR to start their count from the morrow AFTER the High Day Sabbath, they should be counting from the morrow after the weekly Sabbath, but it is obvious that for them to be counting from the morrow after the High Day Sabbath, the High Day HAD to be a Sabbath to them. And this is what John was referring to in John 19:31. That Sabbath was a High Day Sabbath, and NOT the weekly Sabbath. Blessings in The Name, ImAHebrew.