His proposal has been consistent since day 1. He sees "Medicare for All" as the desired end state. "Medical for All who want it" is the glide path to get there.
It's worth watching the entire answer, but the relevant quote is,
"In the case of Medicare for All, which is where I think we need to go, I think the way to do it, by the way, is to make some version of Medicare available on the exchanges as a sort of public option, invite people to buy into it, and if people like me are right -- if it's going to be better and more efficient -- then that's going to be a very quick pathway to Medicare for All, and if we're missing something, we'll find out the hard way and fix it."
I'm interested to see any information you have showing an inconsistency, as I've been following him since probably January and have only heard him talk about this approach and implementation.