There is something I do not quite understand with regards to the so-called non-locality problem in EPR like experiments. The wave function propagates at c, so even when two particles, that are part of the same quantum system, move in opposite directions they are still connected. They both travel along a null interval and thus there is a causal connection between the initial state and the measurement. The same with a single photon, it gets emitted at one place and absorbed at another place but the distance is exactly zero. What am I missing?