A scene where Moridin meets Cadsuane and kills her then, considering that Moridin is pretty seclusive and concentrated on Rand.

I also think we don't really know, if Cadsuane's ter'angreal would alway protects her of saidin. While Setalle Anan believes in KoD that Cadsuane might have a ter'angreal that can disrupt flows of the Power and compares it to Mat's medallion, IIRC we only saw Cadsuane disrupting Semirhage's saidar disguise once. Maybe she isn't protected against saidin, or her ter'angreal works in a way that you have to actively destroy a weave.

Besides that, as Rahvin showed you can even kill Mat with the OP, if you use indirect effects, like causing a "natural" lightning.
Therefore I believe that Cadsuane would always be careful. Of course, since the ter'angreal likely wouldn't protect her against TP balefire, even if she is prepared to counter an attack, it doesn't really matter.

Personally I doubt though, that Moridin or someone else will kill Cadsuane. I rather think Cadsuane will die because of her age shortly before or at TG (this was foreshadowed by her thoughts, IMO).