It is probable that the 'Demon' told Kohdy the truth of Safehold. Either the Archangels provided Spanish as a battle language or the Demon did via his NEAT. At least one English sentence in the Diary must have suggested the Adams and Eves came from some place other than Safehold but, did not outright say so, thus differences in interpretation among the Sisters of Saint Kohdy. Likely the Spanish portions contain the Truth as presented by the 'Demon.'
I agree with the speculation Nynian is the head of the action/intelligence arm of SoSK. She has suspected Merlin was more than his public face, but did not confront him with this knowledge until she needed quick transportation to Zion and back.
So why? Could the Sisters of Saint Kohdy be so divided in the differences of interpenetration in the English of the line(s) that hinted the Adams and Eves came from somewhere other than Safehold that conformation might break the order?
Kohdy trusted Schuler and the Stone of Schuler's mesaage does not jive with the Book of Schuler showing he was probably worthy of trust. We await more revelations in future snippets.
to clarify these points, or are you enjoying playing "I wonder what the fans will guess next," games too much?
Poker