GD Casey was one of seven girls who were equipped with interchangeable brows. Six of those girls (GD Kyle, Masha, Jade, Chantal, Ayumi and Ashley) were originally released and then pulled when problems with the brows were uncovered.. Those problems couldn't be solved, unfortunately, because of problems with the software. Those girls (Casey included) were reworked, removing the brows, and will be re-released at some point.
Thanks for asking!