Irving Weiss, the SEO lead at Vitals.com, shared a thread with me on Moz that in some cases, Google is only showing the reviews rich snippets when the query is a site command.
Here is an example. If you do a site command for this site, you get review snippets:
But if you search for the first result without a site command, the snippets are removed:
An SEO at LeadHub also reported this in the thread saying:
I'm noticing that several sites of mine are triggering rich snippets for REVIEWS when I do site:search, however when I remove the site:search their results are stripped of rich snippets.
Is this common?
Forum discussion at Moz.