What is the test for reversal of a finding that a defendant in a civil civil case improperly obtained secret communications?

1 There is of course a fundamental distinction between this type of "secret communication" occurring in a civil as opposed to a criminal trial. In a criminal trial, the defendant has a constitutional right to counsel and to be represented at each stage of the trial. On this basis, we have held that when this type of error occurs in a criminal trial, it requires reversal unless harmless beyond a reasonable doubt. Bustamante v. Eyman, 456 F.2d 269 (9th Cir. 1972). The civil trial, however, is not fraught with these constitutional considerations.