DL said it was a mistake and reverted the rule to the older version within a day or two of it's introduction.
So, instead of "flights originating/terminating in North America," it's back to the old rule of "flights within or originating from certain countries" -- China is among them. I have found zero DL award availability within 72 hours of travel on the various intra-China routes I chose to search. This includes hourly routes like CAN-SHA. Otherwise you have to issue the ticket in person. But DL has no ticket counter in CAN or SZX. Oh well.
DL also has an unsavory rule of making awards nonrefundable within 72 hours. Were I PM or DM, I would assume that I could get that waived.