Did anyone else encounter an issue in which Orris suddenly starts speaking French (I think) during the Upstream route? My friend and I both encountered this.
No, that's just how it was written - suddenly changing languages at that point was just done to reinforce the fact that Orris there is just part of Iustirho's extended hallucination as the chimera becomes stable; while Aztargal, Zasaroja and the rest of the chimeras are actually speaking to him and not imagined.