Interesting. If I had to resolve this question, I would say that Yoda still believed the twins might have been a hope for the galaxy, but didn't want to give either of them actual Jedi training. Sort of like how he recognized how Anakin may have been the "chosen one," while still deciding not to train him.

Still, it would have been best if Lucas could have at least tried to keep the PT consistent with all of the things that Obiwan had said. The poor old dude is such a total liar now. It's best to pretend the PT doesn't exist.