Yea, it's lifters. It's unfortunately not a rare failure for these trucks.
For what ever it's worth, my fathers trackhawk had it's lifters go out at 105k, and it has no deactivation. They replaced all 16 under extended warranty no questions asked. 6.4L Hemi SRT I had went out at 72k. So, while not a huge case study lol, but it seems any OHV can have them go out, DFM or not.
As long as you have a good extended warranty company, lifters should be covered.