Yes, it was the beginning of Lauds of Easter Day.
In the 1962 books that comes directly at the end of the Vigil Mass. In the 1871 Pustet Gradual it is also directly at the end of the Holy Saturday Mass, there identified as Vespers. Either way it was heard at the end of the Mass following the long series of prophecies and the blessing of the font, so it was well known to the devout.

I looked it up in our Dominican books because I didn't remember see/singing it.
It is no where to be found in the Dominican usage for the Vigil Vespers or Lauds of Easter or the Corpus Christi procession. But I did see in the Liber.
We have taken the Alleluia super psalm antiphons for the major hours and use them for the Alleluia super psalm antiphon for the Little Hours during the Easter season.
Thanks so much. It was just one of those distracted musings that came to mind one day last week.

And, in terms of incongruity, the Vigil as a Vesperal service occurring in the morning was ... another one.

The N.O. Holy Week is annoying, no matter how you slice it. Though some aspects are better than in '62.

Quite incongruous. Meaning the incongruous has a way of becoming traditional, if not Tradition.

I agree the timings of the NO Triduum are different from those of other days of the year. I regard that as a feature, not a bug.
My inherited 1925 hand Missal has three quarters of a page of small print explaining how the early church celebrated the Vigil, and it corresponds closely to the NO. It adds that the church now (ie 1925) anticipates the resurrection by nearly a full day. It does not attempt to explain why, nor give a justification, but this is a text for the ordinary Mass-goer not a liturgical treatise. To those of us brought up in the 1950s on stirring tales of St Patrick defying the High King by lighting his Easter fire on the hill next to Tara, the restoration of a sane time for these ceremonies seemed entirely admirable.

I understand vespera in Latin to refer to evening, the time of the evening star, and of lamp lighting. You don't see stars until the daylight is fading, and you don't light lamps until daylight is fading.
A vesperal service in the latitude of Jerusalem would naturally occur after the daylight working hours, just as people naturally start cooking around then, after work, so as to eat after the heat of the day - that is what they mean by evening.
I deliberately cited an ordinary source, a hand missal for congregational use from before Bugnini was even a student for the priesthood.
Does the obsession with midnight even exist before clocks became common and a "day" was redefined to start at midnight? But I can see why we and the Romans would want to regard the whole time between sleeps as the same day, and that that clashes with the Jewish/Moslem definition of the day ending at dusk and a new one starting.

It began with what I considered a misleading answer over the origins of this Alleluia… it’s attached to Lauds in the 1955 liturgy, but it’s originally, and was always, a part of Vespers once that office officially became a part of the rite. The one knock on what used to be the EF over which many trads would agree is that Holy Week isn’t that old and is a hot mess to celebrate.

But then it devolved into defending the time changes themselves as if the changes were either justified or correct or both. They are certainly not the latter, even if some changes were warranted.

Gregory DiPippo notes that the incongruent text of the Exultet is transferred to the celebration of Lauds in his article on the hours of the Triduum published as a part of the Compendium of the Holy Week reforms. I don’t think that anyone denies that it’s a little weird to anticipate the vigil with a fire sung and the Exultet sung in the morning light.

However, celebrating Pascal Matins in settings other than the monastery is feasible if you anticipate the service. The office is once again reduced to the priest’s private prayer book, because it is simply unfeasible to turn around from the Vigil to celebrate Compline and Matins. Even the reformed vigil of Pius XII makes this impossible.

Pastoral common sense would allow for anticipating the Vigil in this case just as cathedrals anticipated Tenebrae of Spy Wednesday/Holy Thursday before the newly-appointed chrism Mass in the 1955 reform (no longer anticipating those offices is also incongruous with the rite…). Plus the vigil is still anticipated in places with multiple communities, and as you note, some parishes ignore it even though chanceries always send a memo with the correct times.

a_f_hawkins: The source merely repeated what the other authors of the period said without any evidence whatsoever. No one disagrees much about what “vespera” means in Latin, although in the Roman rite, there’s hardly any textual incongruity if you anticipate an office, so long as Compline is celebrated in the afternoon in order to anticipate Matins sometime im the evening or indeed after dark, unlike in the Byzantine rite with the Phos Hilaron. Even the antiphon of the Magnificat at the Paschal Vigil doesn’t help much: the fact is that one Gospel says “evening,” i.e. after the Jewish Sabbath ended without any doubt whatsoever, another “morning.”

But “daylight is fading” is nevertheless not what the rubrics say. They specify after dark. It would be one thing to insist that the vigil be celebrated in the evening in most places where Matins will not be chanted. It’s another to specify after dark or to order that Mass begin at midnight.