Well if you have some pressure on the column lock it wont let the cylinder turn due to the increased resistance. In actuallity, this is a problem that has been around as long as there have been column locks. Its always a good idea to make sure that there is no pressure on the lock and that the wheel isnt turned all the way and held while taking the key out. Its best to make sure the steering wheel has found a position of rest before turning the car off and of course I have also seen people park the car up against a curb for fear of it rolling away and the pressure put on the front tire from the car drifting a bit when they park it has the same effect by putting pressure on the column lock.

BTW, glad you got it figured out 8)