camber problems front wheels

[RodeRoNL]

After changing front tyres the steering wheel was off quite a bit to the left. I thought that it would be a simple alignment job, although I cannot see how a simple tyre change could cause this. The alignment revealed that the left side had positive camber and the right side negative camber. This could not be adjusted. The alignment could be adjusted and the steering wheel centered. The car drives OK (but did that all along, except for the sudden off center steering wheel). Also the old front tyres wore evenly and lasted 35000 km. No problems there too.

Camber values left front were +0.13, right front -0.37, resulting in an out of spec difference of 0.50. Wheels, tyres and suspension have been visually checked, but no damage could be seen. Tolerance is -0.30 to +0.30.

Mystery 1: How can a steering wheel get off by changing tyres?
Mystery 2: What could have caused the camber difference as I am the only driver of the car and I had no accident or mishaps at all.
Mystery 3: Could the guy who drove the car and changed the tyres had a mishap of some sort resulting in a "non visual damage" He took it for a short test drive after he put on the new tyres to reset the tyre inflation control system. Tyres were changed at a Mitsubishi dealership in Germany (I live in Holland).

The guy doing the alignment said that he only saw these values if the car was not completely well repaired after some sort of crash, but honestly I never had a crash and I own the car from new. The Dutch dealer says if the car drives well (and it does) I should not worry.

My thought is that the front camber difference between right and left must have been out of spec from new, but it only came to light after the front tyres were changed (steering wheel suddenly off center). As said, before and after tyre change the car drove well.

So, do we have another item that wheel alignment are out of spec after the rear axle problem, now in the front, that cannot be corrected?

By the way, all other values were well within spec all along, even my rear axle values were very good.