An Apple spokesperson confirmed to MacRumors that future iOS updates will fixed a bug with the voice assistant Siri that violates the privacy of messages received.
The problem is specific to iOS 11.2.6 and the beta version of iOS 11.3. Siri can read aloud potapivka messages on a locked device upon receipt of the appropriate voice commands.
The error does not affect iMessage, SMS, and built-in mail client (voiced only the subject of the email), however, reports from third-party applications are protected. Siri ignores the option «never show thumbnails,» hide notification content on the lock screen.
While there are two tapsoba to solve the problem: disable notifications or Siri on the lock screen.