It can take a while to get accustomed to shoot wide open with lenses f/1.4 or faster. Think for example that if you're doing a closeup and you focus, then re-compose, you maybe have moved your camera slightly changing the angle of the focal plane. For a razor-thin DOF in the case of f/1.4, you'll most likely have the focus somewhere else.
One good thing to do is focus and when recomposing try not to lean camera (and consequently the focal plane) forward, try to keep it in the same plane where it was when you framed it.

The best way to check whether is something wrong or not, is to have your camera on tripod, make some test shots at f/1.4 at various distances and use the microadjustment if necessary. If the focus point is way off when you shoot from tripod, then go back to nikon and tell them if they don't fix it you'll smash their front elements to bits.