The WordPress core team has released an emergency release of WordPress 5.5.3, just one day after the release of version 5.5.2. This emergency release was done to remedy an issue introduced in WordPress 5.5.2 making it impossible to install WordPress on a brand new website without a database connection configured. In preparing for this emergency release, a second issue caused a number of sites to be erroneously updated to version 5.5.3-alpha.
According to the release notes, between approximately 15:30 and 16:00 UTC on October 30, the WordPress auto-update system updated some sites from version 5.5.2 to 5.5.3-alpha. This occurred