This is a very complicated and messy story. I've been trying to get my head around it for a while. This essay by Professor Moss sums up the key information. For more details as they came out, see the recent posts by Brent Nongbri at his Variant Readings Blog. His most recent post, Jerry Pattengale on Dirk Obbink and the Mark Fragment, came out after Professor Moss's essay in the Daily Beast.
I'm not going to try to summarize the situation. And I'm certainly not going to offer an opinion on it. I note the discussion merely for your information. Let's keep an eye on what happens next.
UPDATE: The Evangelical Textual Criticism Blog has also been posting on this story.
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