Lanfear/Cyndane has said in the past that she knows how to overcome warding one's dreams. It appears that she finally broke through Rand's warding at the end of ToM. I do not think Rand has the dreaming ability and it is obvious he is not in control of that dream.

The other thing is the timing of invading Rand's dream. I think the only explanation is that right on the eve of when Rand is supposed to start the last battle Lanfear/Cyndane makes one last effort (or maybe she's been saving this card to play now). Either way, I wonder if Rand goes to the meeting at the field of Merrilor under the influence (partial or full) of Lanfear/Cyndane. It is an interesting idea and I'm curious to see how this plays out.