Curiosa: When acronyms collide

Today's work task: transcribe the text on the parchment ms. leaves used as pastedowns in an old binding. One's from a popular medieval text for medical students, Gilles de Corbeil's De pulsibus -- everything you wanted to know about the human pulse, in verse. The other is from a breviary with some pretty red-and-blue initials, but at this point in my career, if I've seen one ms. leaf from a late medieval breviary with pretty red-and-blue initials, I've seen them all. That is, until I get to the notation for the psalm for the second nocturne of (I think) the feast of the Epiphany:

Iubilate d'o o.t'.p.
Which means "Jubilate Deo omnis terra psalmum" (the first words of Psalm 65), but had me briefly agreeing that yes, we should all praise God for our OTPs ...

My various fandoms have eaten my brain ...