Romanced Emmrich's combat dialogue bugged?

First time posting here so I hope I'm doing it right. Anyhow, my character is currently in a relationship with Emmrich and while he did call her "darling" a couple of times during combat, now he keeps calling her "rook". Is this a bug or are the lines supposed to trigger on rotation and I've just been unlucky never getting the more romantic ones?
(I'm playing on PC, got the game from Steam)