Back in July 2013, the Massachusetts Supreme Court held that confidential communications between law firm attorneys and a law firm's in-house counsel concerning a malpractice claim asserted by one of the firm's clients are protected from disclosure to the client by the attorney-client privilege. Shortly after that, Georgia issued an opinion agreeing with this position. A strong debate followed (see here and here). Oregon was next, and the debate continued.
And now, California Supreme Court has joined the list of jurisdictions recognizing the applicability of the privilege: "The question before us is whether the attorney-client privilege applies to intrafirm communications between attorneys concerning disputes with a current client, when that client later sues the firm for malpractice. We conclude that when an attorney representing a current client seeks legal advice from an in-house attorney concerning a dispute with the client, the attorney-client privilege may apply to their confidential communications." The decision is called Palmer v. Superior Court and you can read it here. Go here for a little more information.