Lanfear wondering who Avi was

Not sure if this has been asked or not, but in TFOH how did Lanfear not know who Avi was?  She certainly should of known who Egwene was.  She was lurking about the tower when Egwene was there, as Silvie she tried tricking Egwene in the world of dreams, and told Rand about her having dreams of Galad and Gwayne.  So she certainly should of known Egwene when she attacked them at the docks.