This isn’t the real “why”. Holding the release back is a political decision. Why hold the story specially? Why not just issue any corrections later? It’s already gone through the same approval process other stories would. The choice to do something different here and treat Trump-damaging stories differently is by definition, biased.
To me, Bari’s response is a manufactured cover up. I’ve followed Bari for years and seen the progression from someone who was a balanced moderate to someone who is slowly developing a strong bias and letting the mask off a little bit at a time. The recent Turning Point townhall was the first big revelation of her bias to the public. But as someone who subscribed to her for years, I’ve seen the progression over time. And the language in here feels less like her usual journalism and more like something carefully put together to deflect.
As for the actual reason - here is what was shared by https://en.wikipedia.org/wiki/Brian_Stelter