Back in May redgameingtech (who admits he doesnt have great sources for xbox side of things), say's he could see Xbox haveing done the same.
However from the xbox series x reveal video, theres a render that supposedly shows the oppersite.
So its unlikely Xbox went the same route, with the cpu.
Necro-bump this 2020: http://gamrconnect.vgchartz.com/thread.php?id=229249
Bumb in 2021: http://gamrconnect.vgchartz.com/post.php?id=9047071