When performing batch POST requests, an error is thrown "No 'Access-Control-Allow-Origin' header is present..."

When Piwik’s JavaScript uses Ajax to POST events (in batches or one by one), there is a missing CORS header in response.
In browser I see "No 'Access-Control-Allow-Origin' header is present on the requested resource" error when a POST request is issued to /piwik.php. Although, events seem to be counted.

Is this a bug or am I missing something?