I created a simple test in Target Premium where I'm just changing the copy and targeted based on a query string parameter. Although I can see the changes in the visual editor, when I activate the campaign, the variation is not shown either when I click the "verify URL" link in the activity or when I trigger the activity. Any recommendations on what to do will be greatly appreciated.
This may probably be due to the reasons that there have been changes in the structure of the website after the test creation in which case the test needs to be setup again. Also you can explicitly create a new activity to double check this and verify that the activity is saved and synced in target.