Here is a blurb from an article [needs Lexis subscription]:
PHOENIX – A professional liability insurer is entitled to deny coverage for an underlying legal malpractice action against a law firm because the insured made a material, factual misrepresentation in its insurance application, a federal judge found Feb. 27 (James River Insurance Co. v. Hebert

Here is a blog article which discusses legal malpractice from a compensation law point of view. The gist? You can sometimes get by without an expert to demonstrate/prove/testify about damages, and sometimes you can’t. Here, one client was successful in obtaining compensation in the underlying case, and one failed, leading to a legal malpractice case.