Yesterday I got one of my heroes (Cianna) to 3 stars, somehow after the "patch" those stars are all gone.
They are not in my inventory either, so it's not like it got undone...

(and no, the stars didn't fail... I she was going around with all 3 stars until now)
I have no pictures to prove it because didn't think it'd be necessary to take pictures whenever a hero got a star.