And what is especially jarring, it also plays in the scene where Astarion has to kill Cazador when you refuse to help him with the ritual (not persuade him out of it, just straight up refuse) and after this cheerful music ends he tells you he hopes you die screaming and leaves the party XD
Lol, that's so bad it's actually funny.

Reminds of some ridiculous vids I saw once with serious movie scenes that had the original soundtracks removed and had cheerful music in the background instead.