In writing about Charlotte's grandparent's - Princess Grace and Prince Ranier - wedding, Mario Testino wrote that "The groom wore a sword, the bride a high-necked froth of lace made by Edith Head, who costumed her movies" which would be a fine, if not flowery sentence if it were true. Grace Kelly's dress was designed by Helen Rose, who also costumed her movies. Edith Head was at Paramount and Grace had a seven year contract at MGM, but was frequently lent out to other studios. As part of MGM's deal to let Grace break her contract and leave Hollywood for Monaco, they insisted that Helen Rose, MGM's Edith Head, would make both her civil and religious ceremony wedding dresses.
(I was able to see this dress at the Victoria & Albert this spring and it is beyond gorgeous in real life.)
My main problem with this sort of blatant error in Vogue is, you call yourself reputable, this would have been remedied simple fact checking. And, what about the times when a subject is less well known to me and you have this sort of error. I might believe you, and then be absolutely wrong myself. Wow, Ms. Wintour, Mr. Testino, I expected more.