The question was not definitively settled in the Church or in his mind at least in regards to specifics, when ensoulment takes place etc. IMO, he didn't teach error, he was reasoning through it and concluding things based on the the information he had. He clearly accepted whatever the Church taught and would readily renounce in error he taught if the Church concluded through her ordinary universal magisterium or through a solemn declaration that he erred. I'm surprised more people have not spoke to the issue her. I have very little to offer apart from what I remember in the distant past.