Here is the NYT account, they sound both confused and confusing. How about "if you have had J&J, it is fine and probably preferable to get a further dose of Moderna or Pfizer"? Yet suddenly it is fine.
And it is the usual story -- people have been doing this for months, and the FDA would not say it is terrible. Because they knew it wasn't. But they wouldn't say so. And now the status quo has shifted, and so everyone will treat it as fine, as if the supposed fears of yesterday never ever existed.