The original romances are fraught with such issues as this one. I'll not claim to be an original with this post, but I simply couldn't find anything despite my best efforts searching the Internet that can help me.
I have reached the point where Viconia says that she will raise her "white flag" to you, and then you spend the night together. Upon the morning, another dialogue immediately reopens where she asks you how you slept: or at least, it should.
For my PC, this hasn't happened. C:AdvanceRealTime and C:SetGlobal to skip to a later dialogue don't seem to be working. I advanced to the dialogue after this one where she asks you about Gorion, but upon completing that line, C:AdvanceRealTime isn't able to set off the dialogue after the one where she asks you about Gorion. I feel like trying to skip a step must mess with some kind of internet logic by which these scripts work.
Such an irritating part of the original games. Any help would be hugely appreciated!
The game is entirely unmodded.
EDIT: Hey everyone. I managed to resolve this. I shouldn't have jumped straight to inputting codes and playing God. The romance scripts of Baldur's Gate apparently do follow their own logic. Whilst Viconia does not speak to you after laying together in the Umar Hills, she will if you sleep in the Windspear Hills. No idea why, but this is resolved!