The Dialogue its actually a Bug.. (start to show up after patch 3)
that dialogue was only supposed to show up when yu dumped her for another romance..
and that dosent affect actually the scene to Play( the romance one) it somehow fix her romance conversations showing up two options for Kiss, how she is feeling.
(as far as i Understood show two options becouse somehow the game dosent fully make yu a couple something like that..)

The Skip with Vlakith stuff.. i Had two times..
But was always coused somehow by Karlach was in my Game as companion..
(were the only two times i try to bring her in a Full run.)
after that never again.. i gave up on her becouse the amount of Problems i Had with shadow and the other Companions with her in my runs.

BTW i Alwyas almost get the Beach romance scene or the other inside the City..
Maybe becouse i only Bring Shadow, Astarion, Lae'zel and Jaheira when i get to act 3 i normally dont Get that Much of events anymore..
So when i Rush Rivinton and Dracos Pass.. almost all the times i get her scene after the Emperor Trying to Lay down with me..
First Vlakith, Emperor Trying bad Stuff then i get her Romance..