This is thanks to a bug where the Mac App Store is unable to differentiate between a boxed copy of the iWork suite and the trial version, and is treating the trial version of iWork apps as a fully purchased copy, allowing users to install the updated (and full) version of the apps for free. Granted the apps themselves are bundled free with purchases of new Mac computers, but those running older Macs are still required to pay for them. This bug has also extended to the Aperture app. We’re sure Apple is working to get this fixed and we’re not sure if already upgraded copies will be reverted once Apple solves this, but we’ll keep our eyes and ears peeled for any updates pertaining to the matter.