Hi,
I just played a game as Marin and chose to do Nagas with the cathedral trinket as my hero power. This hero power is supposed to cast the first spell of your turn a spell a second time. The trinket was not interacting with the new Naga mechanic of cast 4 spells to upgrade.
A lot of mechanics, which require “you” to do something work this way. “You” did not cast the spell a second time, it happened automatically. So it will not interact with theNaga mechanic.