Invading the province of the jury.

Prof. Colin Miller has published an article about Fed. (Mil.) R. Evid. 606.  Prof. Miller argues that, "Rule 606(b) to preclude
allegations of juror bias violate criminal defendants' right to present
a defense."

Dismissed with Prejudice: Why Application of the Anti-Jury Impeachment Rule to Allegations of Racial, Religious, or Other Bias Violates the Right to Present a Defense.

The Military rules of Evidence.
are here.