Subscription confirmation message not displayed

I have two environments setup – development and production. In both environments, I have an “email subscription” page that users subscribe on and subscribe2 settings are identical. This “email subscription” page has some text and the shortcode for Subscribe2.

In development, all Subscribe2 status messages are displayed properly and the other text on the page does not appear. In production, some status messages are displayed properly (and the other text on the page is replaced) and some are not – specifically the confirmation message.

What should I look into relating to the two environments where status messages are sometimes not displayed properly in production? Both environments run the same version of WordPress and the same version of Subscribe 2 (the latest).

http://ww.wp.xz.cn/extend/plugins/subscribe2/