The failures happened on a Autobahn. Thats much closer to a track than to a highway.

 

There's not much more stress on suspension at 250 kph vs. 100kph during straight line steady speed operation.

 

Losing control is much easier at high speed though - particularly if you're trying to avoid a collision with another vehicle.

The damage to the wheel suggests it hit a kerb at speed. The snapped lower wishbone is interesting.

 

If one look at different GT-races with Aston Martin, BMW, Porsche, Mercedes, Audi, Ferrari, Lambo and other supercars, it is not unusual that the rear wheel comes partly or (more seldom) fully off if they touch other cars (rear wheel hitting other cars front wheel) or hits sideways into barriers.

These two insidents do not indicate any kind of design flaws. If there was a design flaw, this would have happened a lot more often. Many of these cars experience a lot more stress when driven hard on tracks. Sliding sideways into track curbs expose the rear wheels to a lot more powerfull and violent sideways forces than driving on the autobahn does.

In my opinion these are just a result from two "normal" accidents - which do happens, and in high speeds easilly tear off a rear wheel.

 

Jaguar started to investigate the accidents.
Stefan