It's more a case of these things not being identified during bench or development testing. Manufacturers have to cram test regimes into a relative short time cycle and to try and emulate a long life of usage they run the units continuously for thousands of hours. This will not replicate long term ownership patterns perfectly but is the best they can hope to do. Real world usage can throw up problems that simply never happened in the development test phase. These early units were designed to be sealed for life and presumably the engineers felt that putting the sensors inside the gearbox casing would keep them out of the harsh environment of rain, snow, salt etc found on road surfaces that cause sensitive items like sensors trouble. They must have realised there were issues at some point after the introduction of this box with their subsequent decision to move the senors outside the gearbox on later versions.
As I said earlier if this becomes an ongoing issue someone in the aftermarket will spot an opportunity to step in to provide a repair solution. With Porsche offering up to 15 year warranty now I'd suggest anyone looking to take out such a policy read the small print very thoroughly to ensure the PDK gearbox is covered and to what extent. It can only make financial sense for them to do so if they offer an exchange service for a unit that has been refurbished by ZF as their dealers will already have the cost of dropping the box out the car so fitting an exchange unit at that point is far more cost effective for them than having the dealer strip the existing to carry out the repair. ZF will be much more efficient at this and be able to fully warrant the repaired unit before it goes back out to the Porsche network. These are relatively expensive cars when new and the running costs do not diminish with age so you have to pay to continue to play as it were with an older model.
If I were Gnil I'd write to the head of Porsche Switzerland and plead the case for a goodwill contribution from Porsche towards thecost of the labour involved in this task andcite the service history of the car within the dealership network and all of his Porsche owning/buying history. From what I can gather Porsche AG are usually helpful in this regard but you need to find the right person in you local distributor to make it happen.
It was crazy to have to buy a new gearbox ( Porsche quote around 19k ) for a simple sensor replacement 
) and coded some Python so I could operate the system whilst I had it out of the car… 
