Why can’t I insert the same chart twice on the same page?

Due to technical limitations, you cannot use the same chart ID more than once on a single page.

For example, this will not work:

[wpdatachart id=33]  
[wpdatachart id=33]

To display the same chart more than once on a page, you’ll need to duplicate the chart first.
Each chart must have a unique ID so the plugin can treat it as a separate instance:

[wpdatachart id=33]  
[wpdatachart id=35]

As a workaround, you can duplicate the wpDataCharts and insert the new shortcode.