There is no doubt that Jose Baez told Casey to stop her smiles and smirks when she walks into the courtroom. So on Day 32 she her best to stifle all of her happy facial gestures. She even had a frown on her lips, yet her eyes were no frowning. This indicates that it was contrived.
She then spots someone someone (perhaps Baez or Cheney)and stare in their direction.
She then raises her eyebrows and gives them a flash of recognition. You can see the tension in her lower jaw protrusion which indicates she is trying hard not to smile.
She looks away and continues to try and stifle a smile.
But she cannot contain herself as she still manages a smirk.
She quickly turns her head to look away and looks down but her eyebrows are still raised in recognition of whom she saw. She tries to stifle a smile as she is trying to obey what she most likely has been told to do.
Jose and his team know that now that the defense is up to bat, it is essential for Casey to act as though she is serious and not be all smiles and lighthearted or flirty.