You're welcome. Here's an early article on the extension. There are plenty more. I'd get it documented right now, even if they don't agree to fix it now. At least you'll have a time stamp.

First it was thought to have been isolated to 11-13 model years but that was found to be false. I'm disappointed in how many fleet cars with the 3.6 that I'm around and hear ticking away. The 3.5's just keep on going for the most part, as do the 5.7's. High mileage and high engine hours and all.

https://leftlanenews.com/2014/06/16...-v6-warranty-over-cylinder-head-failure/