The first read through, I found it odd how she practically stared at herself in her reflection in the wine cup. I have seen people who have had their looks marred, perhaps due to a facial scar, gaze longingly at a photo of themselves before the incident happened; seemingly as a type of mourning over something they feel they have lost forever. This would make sense in Graendals case especially because she held her beauty in such high regards.

On my second, I noticed how her voice seemed to get harder, colder, when she talked about his failures. The one person of the Chosen to whom his failures cost most dearly was Graendal. Not only did he fail to kill Perrin, but also lost the Dreamshard that she was given. She has always seemed like one who would place part of her failures on her tools instead of taking it all on herself. The anger and resentment seems to bleed out of her while talking to him.

All in all, I think that it was Graendal at the behest of Mordrin.