I just spoke with Araj (which put Astarion at 97 approval) and then long rested.
This triggered the romance flag cutscene, same as my previous run.
The conversation I got felt slightly different but I may be misremembering the dialog I picked, or it could be due to minor choice differences I made. The most notable probably being (if they even matter):
There are two triggers for the romance convo that lead to two different versions of the it - high approval and meeting Araj. So, by talking to Araj before the romance convo happened you triggered it. I find that the convo you get after Araj is an inferiour version and I try to avoid it by not talking to her until my character had the talk with Astarion (or rather he with my character).
I played through Act 2 just a few days ago and I got the romance dialogue before I even sat foot in the mausoleum, so not sure why it did not trigger for you, OP. I had talked to Raphael at the Inn though.
During my very first playthrough I had the conversation trigger immediately after Raphael had told Astarion about the scars and I found it fit really well there (same long rest). Whereas I did not really get they same feeling when the conversation triggered too soon. I like that it's layed off a bit. So opinions on this can differ depending on our first experience I guess. I prefer to get it a lot later in Act 2, it came way too fast for me during my latest playthrough IMO.
