On April 9, Apple released macOS 26.4.1 to the public, alongside vague release notes that just discuss that the update contains bug fixes.

The new macOS 26.4.1 update is now available for download

The new macOS 26.4.1 update is now available for download
While Apple hasn’t detailed exactly which bugs this new update addresses, there may be clues from other recent releases. The update comes just 24 hours after Apple also released iOS 26.4.1 and iPadOS 26.4.1.
Both updates applied a fix for one bug in particular. That bug caused some iCloud data not to sync correctly and affected both Apple and third-party apps, including Passwords.