At the end of the movie The Nun, we see that Frenchie's real name is Maurice. And as they are leaving the Abbey, an inverted cross appears on his neck indicating that he's possessed. The scene cuts to the opening of The Conjuring where Ed Warren is giving his lecture & shows the video of Lorraine examining Maurice for where she has the vision of Valak.
IMDB mentions that Maurice in The Conjuring is played by Christof Veillon. But in The Nun, Frenchie aka Maurice is played by Jonas Bloquet.
So, did they reshoot that Lorraine-Maurice interaction with Jonas Bloquet? Or just didn't bother expecting audiences to ignore this continuity error?