Well, it happened to me!
She started an occasional slight knock about a month ago that slowly become more constant. I thought (hoped really) that it was the heat shield on my turbo getting loose and that all I need do was to tighten it up. Alas, no. It was "the rattle of death"!
I have many mods and didn't take anything off. I took my extensive maintenance log/paperwork with me but they didn't need it. She failed the test and I will be getting a new long-block replacement. They will move over my existing turbo, high-pressure fuel pump and intake system to the new engine. He even offered to move over ALL my engine mods from the old to the new engine - for free! I also got a new 2019 Kia Optima LX as my free rental car.
The tech was really cool and we talked a lot about the recall and what they are seeing and suspecting is the issue. While the debris issue was likely real in the beginning, the real suspect is the oil pump/balance shaft assembly. Something starts binding, the rotor plate gets bent and the engine likely is not pumping oil as well as it should and this causes the failure from oil starvation. It has happened to perfectly maintained engines (like mine) with both low and high miles. HOPEFULLY, they have figured this out and have a new, redesigned unit in place for the long-block. All internals are new and of the latest versions (2015 is the last MY for this engine in production), while the block itself might be new or might be re-manufactured and fully inspected. I was also told that the new engine will have unlimited miles and unlimited years for its warranty - something I was totally not expecting!
So really, I got a "Golden Ticket" with the situation! The time-frame could be a few weeks to four months due to the back-logged nature of the replacement. I'll keep everyone posted.
Update (12/5/18): I was just called and told that my new engine arrived and they are starting the replacement process. I will likely get my car back early next week! SWEET!