If the government raises an affirmative defense, does it bear the burden of proof?

If the government has previously claimed the Good Faith Erroneous Interpretation affirmative defense, it again claim that affirmative defense 20 years later in the same jurisdiction?

If the standard of review for the Good Faith Erroneous Interpretation Defense is an objective one, is it proper to take a person's subjective belief into account?

If the government makes a judicial admission that it did not make a violative disclosure, is the government estopped from making a contingent evidentiary admission to the contrary in a motion for summary judgment?

If the government raises an affirmative defense, does it bear the burden of proof?