An intentional express disclosure of privileged communications normally triggers an irreversible waiver, although the disclosure might or might not cause a subject matter waiver. The waiver implications of implied waivers present more subtle issues, because clients can impliedly waive their privilege protection without disclosing privileged communications. For instance, pleading an "advice of counsel" defense impliedly waives privilege protection for pertinent privileged communications.
In United States ex rel. Calilung v. Ormat Industries, Ltd., a qui tam defendant filed an affirmative defense that it "'acted reasonably and in good faith in light of all circumstances and in compliance with all applicable legal requirements.'" No. 3:14-cv-00325-RCJ-VPC, 2016 U.S. Dist. LEXIS 100292, at *5 (D. Nev. Aug. 1, 2016) (internal citation omitted). The court found that defendant's "affirmative defenses go beyond mere denial of scienter to put its state of mind and knowledge of the [legal] requirements at issue." Id. at *14. The court thus held that defendant's implied waiver required it to produce all privileged communications about the applicable legal provisions. But then the court found it "appropriate to give [defendant] a choice": (1) "proceed with its good faith defenses and produce the relevant documents," or (2) "preserve the communications' confidentiality by abandoning the defenses that giv[e] rise to the waiver." Id. at *18.
Not all courts would be this generous, but most courts allow litigants to "undo" implied waivers by withdrawing the assertion that would otherwise require disclosure of privileged communications.