How do you fix a "Parser Mismatched Metadata" error from Open Graph tags?

I'm debugging the Open Graph tags on my site (example page).

I am struggling to fix an error I'm getting from the Facebook Debug Tool. The error is:

Parser Mismatched Metadata:
The parser's result for this metadata did not match the input metadata. Likely, this was caused by the data being ordered in an unexpected way, multiple values being given for a property only expecting a single value, or property values for a given property being mismatched. Here are the input property =>content pairs that were not seen in the parsed result: 'article:published_time => 2012-07-07'

I believe I'm formatting the article:published_time tag correctly according to the docs, with leading zeros on the month and day, a four digit year, and ordered as year-month-day. It also appears in the same order as the examples.

Here are the the raw Open Graph tags:

Meta Tag:   <meta property="fb:app_id" content="407390309287595" />
Meta Tag:   <meta property="og:type" content="article" />
Meta Tag:   <meta property="og:url" content="http://www.zujava.com/how-to-make-a-book-cover" />
Meta Tag:   <meta property="og:site_name" content="Zujava.com" />
Meta Tag:   <meta property="og:image" content="http://assets1.zujava.com/sites/default/files/3781/how-to-make-a-book-cover/book-cover.jpg" />
Meta Tag:   <meta property="og:title" content="How to Make a Book Cover" />
Meta Tag:   
<meta property="og:description" content="Preparing to go back to school can be expensive. Buying book covers should not be one of your expenses because it is so easy to make your own book covers for no cost at all. It takes less than 5 minutes to make a book cover and it doesn&amp;#039;t require any tools or extra supplies. You can make your own book covers out of paper bags, construction paper, bubble wrap, wrapping paper and other recyclable materials that you probably already have in your home. Once you cover your book you can decorate it by doodling on the front or adding stickers." />
Meta Tag:   <meta property="article:published_time" content="2012-07-07" />
Meta Tag:   <meta property="article:author" content="http://www.zujava.com/users/varietywriter" />
Meta Tag:   <meta property="article:tag" content="crafts" />
Meta Tag:   <meta property="article:tag" content="education" />
Meta Tag:   <meta property="article:tag" content="school" />
Meta Tag:   <meta property="article:tag" content="back to school" />
Meta Tag:   <meta property="article:tag" content="easy crafts" />
Meta Tag:   <meta property="article:tag" content="art" />
Meta Tag:   <meta property="article:tag" content="arts and craft projects" />
Meta Tag:   <meta property="article:tag" content="books" />
Meta Tag:   <meta property="article:tag" content="book covers" />
Meta Tag:   <meta property="article:tag" content="how to" />
Meta Tag:   <meta property="article:tag" content="make your own" />
Meta Tag:   <meta property="article:tag" content="arts and crafts" />

Is something incorrectly formatted, or missing?

Don't be worried, it's just a warning (not error, errors appears in red in Debug tool output) and it's not blocking updates of data in OpenGraph.

Just to be sure you can compare updated data with one you posted, currently it seems to be ok.

article:published_time:1341644400 -> 2012-07-07T10:00:00+03:00

If you wan't to suppress the warning message just replace your DateTime fields content in OpenGraph meta tags with UNIX timestamp, and the warning will go away. I've described this in my answer for OpenGraph: custom properties not showing in post providing links to existing bugs on the issue (see BTW at the bottom of answer).