2015 6.4 Hemi

Nobody KNOWS what is causing the cam/lifter problems. Some think it's caused by excessive idling; some think it's caused by VVT and/or cylinder deactivation design. UTG thinks it's because of the lifter geometry; some think it's caused by defective lifter rollers.
Personally I think most of the problems are caused by poor maintenance, extended oil change intervals, poor quality oil/wrong weight oil and poor quality filters.