A keen user at NeoGAF spotted something interesting on the official French website of Square Enix. There was a listing for a new version of Final Fantasy X/X-2 HD Remaster, and this time the platform listed was PS4.
The page has since vanished, but you can still see it in this Google cache version. The story was also picked up by Gematsu, who tried to ask Square Enix for a comment on this matter. They got a reply that was both short and blunt:
"We are looking into this matter and have no comment at this time."
Could be some sort of database issue as was the case with the report about Skyrim coming to PS4 and Xbox One or an accidental slip.