If I recall correctly, Verin Mathwin has gone missing, and she wasn't with Cadsuane and Rand at the manor. She may have made entering Tar Valon her project at the moment, especially since the last time we heard from her, she was thinking about the Horn and who is connected to it.

Also, quite conveniently, the letter she left behind points obliquely at Elza Penfell - it seems that Verin suspects that after Compulsion, a Black Ajah Sister might find her own reasons to keep Rand alive at any cost.