Does the Cuyler v. Sullivan standard for conflict of interest apply uniformly across circuits when assessing Sixth Amendment violations in successive representation scenarios?

In his Se ction 2255 federal post -conviction , Petitioner Robert Sha rp alleged an actual conflict after his attorney’s former client in the same criminal investigation testified against Mr. Sharp at sentencing about the purpose of that represent ation , resulting in an obstruction of justice enhancement and loss of acceptance of responsibility. 1.Does the standard in Cuyler v. Sullivan , 446 U.S. 335 (1980), whic h re quires only a showing that a conflict of interest adversely affecte d c ounsel’s performance to establish a Sixth Amendment violation, apply to successive representation conflicts, as held by the Second, Third, and Ninth Circuits, or must defendants demonstrate prejudice under Strickland v. Washington, 466 U.S. 668 (1984), as require d by t he Fifth and Eleventh Circuits, with the Fourth, Seventh, and Eight h C ircuits expressing uncertainty, given this circuit split? 2.When assessing adverse effect under Cuyler v. Sullivan for a conflict of interest, should courts apply a lenient standard focused on whethe r t he conflict influenced counsel’s strategic decisions, as adopted by the Second, Third, and Sixth Circuits, or a stringent test” requiring proo f that an alternative strategy was factually viable, as applied by the Fourth and Eighth Circuits, whic h ii effectively mirrors Strickland’s prejudice standard, creating inconsistent Sixth Amendment protections across circuits?