iPhone X Email Notifications Cleared from Lock Screen When Unlocked

So when I get notifications, for example messages and emails, I see them on the lock screen. I pick up the phone and use Face ID to unlock the phone to see the preview of the messages before swiping up to go the home screen. The issue is once the Face ID unlocks the phone the email message notifications disappear but the message previews stay. I cannot understand why the phone removes the email notifications when the phone unlocks but leaves the messages. I want to it not to remove the emails notifications on unlock. I cannot find anywhere in the settings to stop this. Thanks for the help.