I got my 2* Wolverine to 144 and opened up his roster page to sell him and re-roster, however he sells for only 17.5k ISO instead of the 65k he’s supposed to. The 100 HP is there as normal.
I had an alliance mate report the same issue with a different 2*, though I honestly can’t recall which one. My other maxed 2*s show the correct sell price.
I tried changing his powers around to see if the game had maybe failed to register he was a champion, but no dice.