For my part, I am inclined to think that Caroline is still living in her "I'll get Darcy eventually" fantasy land. I believe she still doesn't see Elizabeth as a serious threat. Remember, he liked her 'fine eyes' in hertfordshire but then preceded to detach Jane from Bingly on account of her 'low connections'. So Darcy's track record is; that although he may speak of 'fine eyes' he doesn't see this as enough. Or at least-that is what Caroline has witnessed.

So although he may own Elizabeth is handsome, I dont think Caroline yet realises Darcy could overcome his prejudice regarding her social status.

Mind you, Caroline would be more inclined to search for something to pick at because unlike Mrs Bennett, who is easily made fun of, she would have found little about Mrand Mrs Gardiner to reproove.