I just bought a house (built in 1999) and was inspecting some of the electrical outlets. In particular, under the kitchen sink is a split receptacle where the top is always on (dishwasher connected to it) and the bottom (garbage disposal) is controlled by a switch.
Upon inspection, I noticed that the black hot wire from the 3-wire was connected to the 2-wire neutral with a wire cap. I also had to switch off 2 circuit breakers in order to get close to zero voltage from this particular receptacle, so I assume the split receptacle is also on different circuits. I'm not sure what's going on here, I'm just trying to understand what I'm seeing.