USDA’s Risk Management Agency updated their 2021 ‘Prevented Planting Coverage’ in July. This update allows crops planted on insured acreage to be harvested as forage, including cover crops, without resulting in a penalty or reduction of payment if certain conditions apply.
https://rma.usda.gov/News-Room/Frequently-Asked-Questions/Prevented-Planting-Coverage
Scroll down on their page ‘Frequently Asked Questions’ and read the “What are my options for planting forage on prevented planting acres?” sample questions and example scenarios. And the same question is posed related to planting a cover crop.