That's fine, making the "core" of an AI assistant that rights to characters can be laid onto is bigger business than owning the characters themselves.
Why acquire rights to thousands of different character favourites when you can build the bot underneath and then licenses to skin and personalise said bot can be negotiated by the media houses to own 'em.
I can't tell if theyve ruined the Cortana name by using it for the quarter-baked voice assistant in Windows, or if it's so bad that nobody even realizes they've used the name yet.
I've had Cortana shut off for so long it took me a minute to remember theyve used the name already.