They would have done this immediately upon seeing the story; checking the veracity of a single highly significant fact which purports to originate from a known

They would have done this immediately upon seeing the story; checking the veracity of a single highly significant fact which purports to originate from a known source doesn't take a week. Anything more than a half-day delay in responding is significant; they could have produced a repudiation video by now. This doesn't necessarily mean that the story is true, just that the campaign has made a deliberate choice.