Am I crazy, or were Astarion’s lines re-recorded? They sound different to me - like maybe it’s a different actor or the intonation is different?

Hmm... I am not 100% sure, but I believe he sounded the same now when I started my new playthrough as last time...

There are some outright new lines for all of the characters I believe, and some are in existing conversations. For example, I was pleasently surprised to discover a barb aimed at you if you're a druid and tell Asterion not to chomp anything you can have a conversation with. Gale's also got some new lines too, specifically when he's explaining he needs to succ magic items but not explaining why.

You are not crazy, I noticed that too. However, I don't think that they needed to re-record -- usually voice actors do a handful of passes at each line, and these can also be tweaked in sound prod to the director's heart's content. Maybe they went back to the archive and picked a different take?

Personally I would take a Terabyte's worth of Neil Newbon just saying "Hello, lover." in Astarion's voice, that's my dream ASMR.

The new lines have been a pleasant surprise.

I watched some BG3 sex stuff, his voices is quite creepy. Vampire stuff definitely.

Very understandable

And I love my character`s reaction when Astarion says that, she's got a big smile on her face and looks quite smitten with him. It's very cute and funny, especially when I play as a high-charisma character who would usually be the one to charm others. I`m very curious where this romance will lead, especially when you are playing a "good" character.

Personally, I think that Neil Newbon's acting/voice acting for Astarion is perfect; to me, it's some of the best voice acting I’ve heard so far. He really brings Astarion to life as a very complex, nuanced character.
And the voice acting for all our companions, and all the NPCs, is really good.

Back to the topic:
In my current playthrough, I have not noticed any changes in Astarion's lines, but I have not reached Grymforge yet. I am very excited about the new content.

speaking of other characters voice acting, it kinda surprises me when I found out who's Gale's actor. He literally just sounds (and looks) like Gale. [video:youtube][/video]

It's the funniest thing, I can't hear that clip.

Gale, what are you doing in London?

The voice acting cast for Baldur's Gate 3 - of course including the narrator, sorry I forgot to mention her in my previous reply - is just perfect. To me, it adds so much to a game when you have good voice acting. Bad voice acting is the most immersion breaking thing to me.