Premature Engine Failure

My 2017 Pacifica with 82,000 miles started with a message when I turned the van on indicating the "automatic off/on system was unavailable." This went on for 2 days until the engine light came on. Took it in to the dealer and was told a "misfiring" code was on, turned out to be a coil that needed to be replaced. Was recommended we change the spark plugs too. Within 24 hours of these these repairs, the "automatic off/on unavailable" message was back on and a day later the engine light. Took it back to the dealer and was informed one of the spark plugs had blown and essentially we had premature engine failure. Has anyone else experienced this? We are set to pick up the car this week, but I am wondering how common of a problem this is with the 2017 mode. Thankfully we had purchased an extended warranty when we bought the car, so it is covered, but this does not bode well for the longevity of the vehicle.