I keep forgetting though.

I've always wondered if Rand left something out which made Narishma angry. Maybe he subconsciouly left something out or something with LTT's influence made him leave something out because deep down inside he wanted to see Narishma get killed over it, even though he wasn't consciouly planning it. Or maybe it slipped his mind because Rand is losing it at this point. He does act pretty stupid and highly overconfident through a good deal of this book. It's not a case of bad writing forcing him stupid, he's losing his mind.

The idea that the Forsaken might have futzed with it behind his back is an interesting idea that hadn't occured to me though.