Is this a bug or April's Fool?

[Cthulhu]

The Aprils Fools cosmic talismans drop as 3*. Getting them to lvl 30 costs 1,365 million. But then I get an "Evolve" prompt that will get the talisman back to Lvl 1



Is this a bug or a practical joke?

I did try it once, and indeed it goes back to 3* Lvl 1 and costs 1,356 mill to get it up to Lvl 30. Good thing that force-closing the game prevents the loss from being written to the server.