My situation is even more bizarre. The 2019 return (filed in February 2020, as it was exceedingly simple) reported the taxpayer as deceased in 2019, and the check is made out to (Name of Taxpayer) Dec'd. So it's not like the IRS doesn't have the taxpayer recorded in their system as deceased in 2019.

I think the best approach is to sit on the check for a month. Maybe the IRS will get around to issuing guidance.