That would hardly be surprising. He didn't oppose the whole thing, just (according to what we can glean from published reports) the "green" part and the overall cost. If Biden (or his handlers) hadn't had the delusion that a squeaker of a Presidential win, a diminished majority in the House and only holding the Senate by the VP's tie-breaker role was a mandate for radical change, they'd have never gone along with the left wing of the party in offering that bloated bill and would have put forward something Manchin would have supported from the beginning.