I'm not very active on social media (mostly reddit) and I've never seen anyone complaining about Karlach until I went here. The view I saw the most often so far is that the game is GOTY material but Emperor vs Orpheus conflict is done poorly/feels rushed. Nobody ever mentioned Karlach outside this thread. But I decided to dive into the issue and verify what you said and the biggest "complaint" I found about Karlach was that she's not coded as lesbian character (which is kinda weird because none of the companion's sexuality is pre defined) but once again, it's twitter so it doesn't surprise me.
As for VAs, no, I don't think they'd air something that could have potential spoilers, it was just a slip up about the act 2 and they played it as a joke
I can tell you're not active, because here's a sample of what you can find on Reddit:
