Stumbles at idle

I have had this 6.4 for a few months now. In general, it has been an amazing truck, especially after I deleted the emissions crap and put a DPF-R+ on it. The best fuel economy I got before deleting was around 14.5. One tank last week i got 18 in mixed mountain road (Yellowstone Park) and freeway driving.

One thing I have noticed is that the motor stumbles at idle. It has a major stumble, then 11 seconds later there is a small stumble, then at 19 seconds it has a major stumble, count to 11 a small stumble, and the pattern repeats like this. It does this with or without the DPF-R+ economy tune.

Has anyone seen this before?

Thanks!