Google posted on the data anomalies page for the Google Search Console that they have downgraded the structured data errors from errors to information notes.
So for "missing structured data" and "invalid structured data" errors in the report, they are no longer being reported as errors but rather "informational notes." Google said they "downgraded" this because they no longer invalidate your AMP pages.
Here is the full note:
Some AMP pages may see a drop in errors reported. This is because the "missing structured data" and "invalid structured data" issues have been downgraded from errors to informational notes. This downgrading was done because an AMP page no longer needs a structured data element to appear in search results.
Here is a picture of the report:
AMP error reporting came to the Google Search Console back in January and they began notifying users of it the month after and they updated the report in May.
Just to be clear, you still need structured data to show up in the top news carousel.
Forum discussion at Google+.
Update: Days later, Google posted something on this on Google+ as well.
