Any difficulty in turning the key I would believe is an ignition switch problem. In this case probably not a problem with the electrical portion but the mechanical portion.
However, as I have mentioned before Porsche techs no longer -- haven't for years in fact -- distinguished between electrical vs. mechanical but replace the entire switch assembly.
But before condemning the lock, let me ask these questions:
Do both keys, the valet key even, manifest the same behavior? I'm thinking maybe the key you are using is worn or not cut quite right, is marginal, and this could account for the behavior.
Does the steering wheel feel as if it is frozen? I sometimes park a car with the wheel turned and the wheel binds with the steering wheel lock which requires me to turn the steering wheel to relieve the pressure so the lock works.