Update 2/8/21
This issue has been fixed by Windows in this Windows 10 update, February 2, 2021—KB4598291 (OS Builds 19041.789 and 19042.789) Preview (microsoft.com).
- Addresses an issue in which using local Service for User (S4U) affects Data Protection API (DPAPI) credential keys and causes users to sign out unexpectedly.
I am updating the Outlook Known Issue article to reflect the same, Outlook and other apps won't remember password after Windows Updates - Outlook (microsoft.com).