Keeps laughing in Californication?

I've watched the first 4 seasons in fairly quick succession lately and I keep noticing Karen keeps smirking and laughing in general conversations, even when Hank and her are arguing. Is she supposed to be doing this? Or is it (dare I even say it?) "bad" acting on Ms McElhone's part?

At breakfast when they're discussing quite serious stuff with Becca, at dinner when Hank is with the lawyer, even when she comes to visit him in the hotel before he''s about to go on trial.

Now, it's a beautiful smile make no mistake about that, it's just... it seems like she's breaking character on many occasions, like Duchovny is cracking her up and they haven't bothered to do a retake. Has anyone else noticed this? It really has started to bother me and has even started turning me against Karen to the point where I don't think Hank should be going after her....