Your symptoms may be related to a sticky steering lock bolt. This thread explains what I went through.
Steering locking mechanism problem - how I resolved it.
I'm not sure of this but it could be that the bold binds and prevents the key baril and the electrical switch from returning all the way to the 0 position. A healthy bolt will make a loud clunk when it slides into the locked position after you remove the key. The unit I fixed in the above thread does this. On my current Boxster the key was very hard to turn, especially in lower temperatures. I tried to lubricate the bolt without removing it and although it is improved it still does not clunk and it takes a couple of seconds for the electrical switch to make it back to the 0 position.