So how did this happen?
It seems highly unlikely that ABC's Jon Karl would have distorted the meaning in this way. So a much more likely explanation is that the source of the leak - quite likely congressional staffers who were allowed to review the emails but not make copies - took notes which were misleading, either willfully or through wishful thinking. Needless to say, reviewing notes taken by an interested party (and I don't know for certain these were notes from a House Republican staffer but it's awfully likely) is an inherently dicey business. Especially if you're not entirely clear with your readers what documents you're referring to. And on that count, Karl fell a little short.
Near the top of his original piece, Karl writes "White House emails reviewed by ABC News suggest the edits were made with extensive input from the State Department." That's pretty clear. And in the article itself he uses quotes for what were purportedly the text of the emails. At other points in the original article, Karl seems to allude to the fact that there were notes as well. Read the piece to make your own judgment on that count. (Late Update - 6:16 PM: On air he seems to have been even more clear that he'd reviewed the actual emails.)
It now seems that the ABC spokesperson jumped the gun because clearly the accounts differ substantially and Karl gets that. He says in a new piece that he asked his source to explain the discrepancy and got this response ...
I asked my original source today to explain the different wording on the Ben Rhodes e-mail, and the fact that the words "State Department" were not included in the e-mail provided to CNN's Tapper.
This was my source's response, via e-mail: "WH reply was after a long chain of email about State Dept concerns. So when WH emailer says, take into account all equities, he is talking about the State equities, since that is what the email chain was about."
I guarantee you Karl had a sinking feeling in the pit of his stomach when he saw that explanation. Because that explanation by reference to earlier comments in the thread is pretty weak. Karl's follow on piece is entitled "More Details on Benghazi Talking Points Emerge" but the substance is, 'How the Story Changes When I Realize the Notes I Was Using Weren't Reliable.' The answer here is that Karl pretty clearly got burned by his source. But he at least seriously singed himself by making it really, really look like he was looking at the emails themselves when he wasn't.