The recall for the Bosch O2 sensors is because they are known and have been proven to go bad. If you're using your original sensors, that's probably what has happened, the sensor crapped out. 2 of mine died on MY2108, which is a few years newer than yours, and likely far less mileage If you've been running those downpipes for a while with no issues, I'd suspect O2 sensor went bad. I know a warranty extension doesn't help you get new ones, but it does show that there is a known and common issue with them.