For articles, Google now wants all of the properties marked as Required here – https://developers.google.com/structured-data/rich-snippets/articles
If you look at the Microdata code example you’ll see the HTML markup that would have to go into the body of your post (the content area). They do have some alternate JSON-LD markup that we can use and place in the head of the site, which is where All in One SEO Pack hooks into, but we have reviewed and tested that alternate markup and it does not include all of the required properties that they now want so their testing tool still returns errors.
Not having Schema.org markup won’t affect SEO. It’s impossible to say whether having incomplete markup will affect SEO. This is so new that Google has only just updated their documentation and testing tool, they still haven’t updated their markup helper tool.
We’re going to be testing different options and will look to have support for this soon.