I have the following RDFa rich snippet at the top of a web page (ref: https://support.google.com/webmasters/answer/146645?hl=en#aggregate):
<div class="site-reviews">
<div xmlns:v="http://rdf.data-vocabulary.org/#" typeof="v:Review-aggregate">
<span property="v:itemreviewed">[Product]</span>
<span rel="v:rating">
<span typeof="v:Rating">
<span property="v:average">5</span>
out of
<span property="v:best">5</span>
</span>
</span>
based on
<span property="v:votes">8</span> votes.
</div>
</div>
However, rather than showing the usual stars in the search result, it displays the text result "[Product] 5 out of 5 based on 462 votes." as the meta-description. Where am I going wrong?
*UPDATE (anonymised) google search result below: