I tried it again, and nothing happened. So I went to a different game where I'm the GM, and it loaded fine, with the following date
Added to Vault on 01/01/23 from the Bestiary game using the D&D 5E by
So I tried the first character again, and it saved showing the following date
Added to Vault on 12/31/22 from the Age of Kyuss game using the D&D 5E by
Not sure if that was an earlier attempt finally showing up. I've got a lot of copies of the latter, so maybe that's an issue.
FYI it is still 12/31/22 where I'm located.