The 9a1 is not immune, for sure. Here is the inside of a 4,465 mile engine that I have my hands in now. These things were noted when we I disassembled the engine to take it from 3.4 to 4.2 liters for a 2012 Cayman R. It had no symptoms, or known issues and had never even had its first oil service. It did make lousy power on the dyno and upon teardown I found out why.
First is the worn cylinders (all of them looked like this)
Then come the broken piston rings
Then the worn lifters
Then the root of the issue, a missing O ring from the anti-aeration side of the main oil pump which leads to the de-aeration swirl pots
The oil was heavily aerated and lost film strength creating these issues. The car was bought new by the owner who sent it to me and was untouched from the factory. Only MY hands have been inside it. Missing parts from the factory? Yep and if this one had them, it can happen again.
As we get evolve the 9a1 engines we have also found valve guide wear and other issues. We already have 3 years of development under our belts with the 9a1 DFI engines and the deficiencies are becoming more clear with each one. Others won't see these issues for 5-6 more years, more than likely.