As I'm sure most are aware, Brandon said that something that happened or began in tSR-LoC will have major significance in the next book. He said it was not much discussed, and he was surprised it was not discussed too much. That it was something that seems innocuous, but will have major ramifications in the next book, like
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FOR MISTBORN.






Vin's earring.

What can this be?

I think one possibility is the dice in Mat's head. We know these started in tFoH, and RJ has said there is something odd about them (he compared it to the Dark One's own luck, IIRC).

My theory is that the dice are a "gift" from the Finns. Contrary to common belief that they act like a warning system, I think they exist to control, chronicle and send back to the Finns any event of significance to Mat's life. I think this is the way the got the memories of all those people they stuffed into Mat's head. This is also how the Finns exert some influence on the world.

Like he thinks, they do have some way of seeing through his eyes, and the dice are it.

I think the dice will warn the Finns that Mat is coming to rescue Moiraine. They'll be able to predict his moves, making it impossible for him to win.

Mat will learn how the dice manipulate him towards certain decisions, and at the critical time, will disregard them, and his luck, thus blinding the Finns and letting him win.