I thought prosecutors knew they couldn’t comment on exercise of right to silence

At trial, the Government repeatedly sought to use Edwards’s silence after he was Mirandized as substantive proof of guilt as well as for impeachment purposes. Over Edwards’s objection, the Government emphasized in its closing that Edwards had remained silent after law enforcement showed him the contents of the suitcase, suggesting a culpable state of mind. The Government in its brief and at oral argument concedes that this was error under Doyle v. Ohio, 426 U.S. 610 (1976), but urges that the error was harmless.

So says the Third in United States v. Edwards.  Result–new trial.

And, for those who follow this issue of how the prosecution and appellate courts seek to forgive such error.  The court noted:

Nor did the District Court’s belated and ineffective curative instruction after the parties’ closings had been completed mitigate the effects of the Government’s conduct.