Cupra Leon Gear damage after 11,000 km?

Hello, after only 11,000km my Cupra Leon (BJ 11/20) failed with a gearbox error. The first diagnosis was that a flat assembly was defective, it was changed, but it did not succeed. Now the complete gearbox should be replaced. The car is practically retracted… It is wrapped up as a guarantee case… But I’m a little surprised, is you familiar with a similar case? Is there perhaps a consultation error here? Or was it just bad luck in the end?