Entries using the pages module can only have a status set as CLOSED. Both existing and new entries.
EDIT: The status group for the Channel used for Pages did not get carried over in the update. Assigning a status group fixed the issue. I am assuming that when the site was originally built in 1.6.4 that a status group was never assigned and it used the default status group as a fall back. This wasn’t accounted for in the upgrade process. Thats my uneducated guess anyway.