As discovered by @plain hill, Je-Ne-Viv can be unlocked in the Foscari Adventure early by enabling Endless mode in the 1st stage and getting to 30 minutes, allowing you to access her much earlier than seems intended. Not only does this mess with the balance of the adventure somewhat, it can also lead to confusion for players in Genevieve's unlock asking for "The True Terror", which many would assume is Je-Ne-Viv given their available options (but please don't change the wording on that it's amazing lol).
I was not the one to discover this bug, so I don't know what version Kavaliro was playing on. I do know they were on the Windows Store version, however!