In KoD Semirhage poses as the Daughter of the Nine Moons to capture Rand. However, when Rand meets the real Tuon in TGS, he doesn't indicate that the woman is familiar to him from his recent encounter with Semirhage (just that he saw her through the swirling colors with Mat), but is rather surprised how small she looks like, etc.

So, do you think this is a mistake? Or did Semirhage actually didn't disguise herself as Tuon from some reason, although she knew her very well, but as another dark skinned not that small woman? (this might be problematic, though, if the sul'dam, who joined Semirhage, knew Tuon's real appearance)