Since the update (1.12.5), there’s been a significant change in the marriage dynamics between mortals and vampires within my game. Previously, it was challenging and made sense that a 2000-year-old foreign vampire would not simply marry a 55-year-old innocent mortal. However, this restriction seem to be gone now even with a fresh save.

Now, not only can my ‘inconsequential’ courtiers marry vampires, but they can also wed ancient vampires who were previously difficult to marry, even for vampire courtiers. For instance, I successfully arranged a matrilineal marriage between a random elder lady, who joined my court after a hunt and Kli Kodesh, a 5th generation vampire aged now 1345 years.

More examples:

Bjorn Garinson 'Sole Survivor', 732 - 6th Gen - Childe of Dark Raven
- accected a matrilinear marriage with my 56 year old mortal.

Abaddon 'the True Explorer' , 678 - 7th Gen
- accepted a matrilinear marriage with my 55 year old mortal of a different faith 'Via Christi'

Andrew 'the Archangel, 1204 - 5th gen
- I could get him into my court by marrying him to my random 43 old mortal. Nice and easy 43 prowess for the army.

I DO have promising prospects. Gives me 50+ to those marriage acceptances, but even so, that game has become far to easy compared to the 1.12.4 versions.


TLDR:
The " I am to old for this ♥♥♥♥" and "Ugh, a human" modifers in marriage are missing since 1.12.5, trivialising the game difficulty