How to theme simplenews newsletters in D7?
This happens because this is the default HTML to Plaintext conversion that Drupal is applying to all mails.

If you don't want this, either adjust the templates (you can find them in the theme folder, just copy to your theme and start adjusting it) to avoid HTML or enable a module like Mime Mail that allows to send HTML formatted mails.

No idea why the title is cut off.