Mine too.
Gotta jump in here because my ATS leaked also. If you buy this manifold, by all means when the box comes, check the bell fit. As I understand it, the bells should be snug enough to require a rubber mallet to drive together or better yet, put the center in the freezer and the outer sections in the oven. If they slip right together, the fit is too loose.
For now, mine is not leaking. I took some shim stock and shaped it to match the bell and put it together. Guess the gap was tight enough for the carbon to build up.