They don't need to be consistent, but they should have at least offered some form of explanation other than just having it be. It doesn't fit with the established pattern they've set up for that world, and it comes off as lazy writing. Just have her turn evil "because powers" instead of giving her character a well defined arc where it's believable that Caitlin would choose to go bad on her own. Overall, I thought this was a decent episode. The future stuff was fun, but damn that wig on grant was a bit rough. Someone needs to tell future flash to not base his hairstyle choices off Tobey in SM3.