(July 22, 2019, 7:32 AM EDT) -- BOSTON — An insurer on June 18 filed a brief in the First Circuit U.S. Court of Appeals contending that a district court erred when it ruled that a second insurer, which was sued in an underlying case, did not owe an apartment management company a duty to defend a property damage lawsuit (Clarendon National Insurance Company v. Philadelphia Indemnity Insurance Company, No. 19-1212, 1st Cir.)....