I'm chapter one of peace talks Carlos says that McCoy sent him to tell Harry about the peace talks.
But in chapter two, when the black staff comes to visit Harry and yell him the council is taking a vote to have him booted, he acts like he doesn't realize Harry will be working security and therefore not be able to follow his advice and make overtures to the council.
I find that extremely strange. How could Carlos be sent by McCoy to inform Harry of the peace talk but then be oblivious to the fact that this would set Harry up for failure when the council takes it's vote?
IIRC Carlos indeed said that McCoy sent him to inform Harry about the peace talks. Just to inform him.
On the other hand Carlos had free choice as chief of security about who to add to his team, and he chose Harry.
So no lie there. And no forgotten knowledge.
Just some odd thought, that McCoy shouldn't have been surprised by Carlos' choice. But on the other hand, maybe he was surprised, because he knew how Carlos thought about Harry.