Had to dig into it, this site says there is a Calendar rule that necessitated the change:
"The Solemnity of the Annunciation of the Lord celebrated on March 25 each year is impeded by Monday of Holy Week in 2024. According to the Universal Norms on the Liturgical Year and the Calendar no. 60, the Annunciation is therefore transferred to Monday of the Second Week of Easter, in this case, April 8, 2024."
Interesting!
Had to dig into it, this site says there is a Calendar rule that necessitated the change:
"The Solemnity of the Annunciation of the Lord celebrated on March 25 each year is impeded by Monday of Holy Week in 2024. According to the Universal Norms on the Liturgical Year and the Calendar no. 60, the Annunciation is therefore transferred to Monday of the Second Week of Easter, in this case, April 8, 2024."
https://doy.org/the-solemnity-of-the-annunciation-of-the-lord/