I was thinking much the same as this article. The standard policy was to release stuff like this the Thursday before the election. Releasing now, when 95% of the country will get to see him in 2 more debates before they vote, gives him a heck of a lot of time to turn it around.
Given early/mail voting these days, probably releasing this 10 days before the election would have been much more effective.
NBC had planned to air this after the debate but it was leaked to WashPost Friday.
Guess it’s marginally better to be able to respond at the debate. I think Trump had other, better plans for the nature of the debate.