If you are saying that you already have these terrain paints in your game, and when installing a lot that also have them you saw no problem, this is normal. You should in fact untick them, otherwise you'll have copies of it, if you renamed yours, or the game will simply tell you that these CC already are installed. The problem arise if you untick them and do not have them in your game.

That's what I'm saying

Okay good, so they work like any other CC. If you already have it/install first, it will be in the lot.