Apparently Ansys AIM 19.0 does not consider imprinted faces when meshing, and 19.2 does. By removing the imprinted faces, I was able to make a non-conformal mesh in 19.2, but then I have to live with that the non-overlapping faces are assigned as insulated walls (please confirm this is the case).

Also, 19.2 seems much slower than the 19.0 version, but as long as it solves my problem, I'm fine.