Unlike a “vigil” Mass (or perhaps more properly an “anticipated” Mass) on a typical Saturday evening, the Vigil Mass of Pentecost (Simple or Extended) is a different Mass from that of the Sunday, with different readings, chants, and rubrics.

The Sequence is not specified in the Missal rubrics, though, but in the Orders of Readings and of Song of the Mass. In those books, the Sequence is specified for Mass During The Day and not for the Vigil Mass. So that's what you do.

Of course if you are doing the Pentecost Mass During The Day on Saturday evening, you might as well do the Sequence too, if the priest wants it.

It's sad, but I can readily fathom why that would be so in many places:

1. Most places don't do the entrance/offertory/communion Propers at all (they are, after all, free in that regard).

2. Most pastors would likely consider that, unlike the very differently scheduled Easter Vigil, the congregants who decided to attend the regularly scheduled Saturday evening Mass have not contemplated a longer liturgy that deploying the proper vigil liturgy would entail - and that it would likely be a stretch for many music ministries at the time of year Pentecost typically falls.

Not to downplay preaching on the readings of the day, but you can preach on other texts. Or weave between texts — the extended vigil isn’t quite the same as the pre-55 vigil, which is still preparatory in nature, so it’s not as odd to return to Saturday’s readings on Sunday.

Or just slip something in braces to change the verbs. I realize that this isn’t typical, but it’s not a bad solution for a problem that occurs a handful of times per year. Plus, I doubt that clerics write four sermons on Christmas.