User blog comment:Morganaforever/Episode Review: A Lesson in Vengeance/@comment-5364525-20121118021742/@comment-4650675-20121118143019

I thought something similar. Initially, Gwen was one of the reasons for Arthur's demise. Since in Merlin Gwen is supposed to be a very good character, all her flaws have to be the result of magic (like betraying Arthur with Lancelot or becoming a traitor by joining Morgana).