What clinched it for Egwene is the same that disturbed Cadsuane: Elaida's sisters, especially Reds, serving Rand like they were his servants (IRRC, she doesn't know they swore fealty. She only got reports that they weren't prisoners yet were serving Rand in odd ways... and ironically that is probably largely thanks to his "abuses", like forcing sisters to serve tea that made an impression on E&E.. whereas the rest of their "service" wouldn't etc.)

For the Rebels there's also the highly suspicious fact their embassy has gone totally silent.

I agree Verin thinks she got away with it without raising any suspicion, so had no reason to reveal this to Egwene, though there's possibly a report about the compulsion and which sisters with Rand are BA in her ciphered notebooks. It is more a matter of whether Egwene will have time to spare any time soon to decipher all these notes to find this information. I get the feeling she won't, unless she decides to set Brown sisters to do it. Otherwise the deciphering of the "full story" of Verin's adventures will have to wait for after TG, Egwene keeping to the essentials she needs, and which Verin conveniently summarized/identified.

I also get the feeling Jordan had no intent to "solve" this issue before Rand and Egwene meet in person. There's not really a point in building up this "conflict" between Egwene and Rand (the compulsion of sisters being one aspect of it, the BT deal and Taim likely to become the primary aspect of Egwene's anger with Rand soon, especially if Logain decides to come to her) if it peters out before Rand and Egwene have a face-off, which is most likely toward the end of TOM, as it happens.