Here's a Link to his original report. Even when he says that there was no sign of asphyxia or strangulation he still says that kneeling on Floyd's neck was a contributing factor in his death. He said that the action was "inherently dangerous" which is a requirement to meet the 3rd degree murder charge. So no pressure. Not a matter of being wrong the first time or the second. He had that opinion all along.
Since the guy died of fentanyl, meth and a heart attack as well as other factors the prosecution will have their hands full proving that the cop caused it all.