“Diocese that stands” probably indicates OF. To my knowledge, kneeling is standard in the EF even in dioceses that stand.
I live in an archdiocese that stands, yet I kneel throughout the Eucharistic prayer and again after the Agnus Dei. In my parish only two of us do this systematically. Chapter II, section II, item 43 of the French GIRM says:…] Là où il est de coutume que le peuple demeure à genoux depuis la fin du Sanctus jusqu’à la fin de la Prière eucharistique, et avant la communion quand le prêtre dit Ecce Agnus Dei (Voici l’Agneau de Dieu), il sera bon de conserver cette coutume. …]
“Where it is the custom for the people to kneel from the end of the *Sanctus *to the end of the Eucharistic prayer, and before Communion when the priest says Ecce Agnus Dei (Behold the Lamb of God), it would be good to preserve this custom.”
The key phrase is “where it is the custom.” I do not know whether it is the custom to do this in this archdiocese, but no one has tried to stop me or the other guy who kneels. YMMV.
Unity does not mean we’re all doing exactly the same thing. If it did, we’d probably all be sitting because there are people who can neither stand nor kneel.