When a backup is restored from Managed Backups using snapshot-installer.php, the site gets restored but the character encoding gets messed up. This happens on a fresh database and was tested more than once.
The current DB encoding on a source site is "utf8mb4_unicode_ci". That same encoding was used when creating a fresh database. It's also used in .sql files inside snapshot backup .zip file and the text in those files seems to be properly encoded (all the characters are fine). But something happens "on a way" during restoration process.