When did Nynaeve see Asmodean? In The Fires of Heaven: Meeting [chapter 14]:

"I have something else important to tell you," she went on after a moment. "I think the Forsaken are planning something." It was not the same as telling them about Birgitte. She made it seem that she herself had seen Lanfear and the others. In truth, Moghedien was the only one she could recognize at sight, and maybe Asmodean, though she had only seen him once, and at a distance. She hoped neither of them thought to ask how she knew who was who, or why she thought Moghedien might be skulking about. In actuality, the problem did not arise from that at all.

TSR ch 39.

Thank you. I knew it had to have been in Tel'aran'rhiod, but I could not reason out when.