Has anyone else seen this situation?

2020 Form 1040.

Some payments made with husband’s SSN, a couple payments made with wife’s SSN. Return filed on time and full paid.

Out of a clear blue sky, IRS sends notice last week for balance due of five-figure amount, including interest and penalty. The payments not being credited are those made with wife’s SSN.

Checking online account for both spouses, all payments show up, and applied to 2020.