There is a known bug in the rewardStyle WordPress widget. For many users, when the rewardStyle plugin is updated, it will deactivate. This is unrelated to your <em>press theme or its compatibility with the rS WordPress widget!
If your Shop the Post plugin is only displaying rewardStyle shortcodes, we recommend going to Plugins and ensuring your rewardStyle widget is set to Activate. Typically, if you have recently updated your rS Widget plugin, this is the culprit! Re-activating the widget should solve the issue completely.
If your widget is activated and you are still only seeing shortcodes, email us at firstname.lastname@example.org, and we can assist you with troubleshooting further.