I hope this is a cache bug of google. Already tested this with structured data testing service and mentioned that I don’t see any problems with schema markup. But as I see all codecanyon items were affected on this, even most popular visual composer plugin.
SERP results very often don’t include ratings. It is not related to specific websites, it is simply the way Google works, and there is no way to influence how, why and when the ratings is displayed in results regardless of the testing tool results.
I got many times that behavior for my sub-sites … It’s not a bug, sometimes google read this schema and sometimes not. But overall I think that they will be removed soon as SEO industry use it much to often