Quick and easy DD16 fueling issue...hopefully

So 2015 Coronado (factory, not glider) DD16 600hp. New to me a year ago.
Before I bought it, the prior owner took it into Premier trucks in Portland oregon for a coolant in fuel and fuel in coolant issue. I have the receipt, the repair was done, and the entire fuel and coolant systems were flushed twice, including the fuel tanks.
Tanks are still spotless inside, and Davco is barely above new line.
Trucks runs awesome. Never misses a beat, easy to drive, I like it better than my X15.
So cruising down the highway at 65mph, 1300ish rpm, it is in it's sweet spot and a real joy to drive. Couple hours go by, coffee needs drained, so pull over, set idle up to 800, maybe 5 minutes go by as I do a quick walk around. Get back in, go to accelerate, and it starts acting like and old carburetor gas pot just about to vapor lock. Baby it up to speed, and again, runs like a top,....till next stop. Could be traffic jam, long traffic light etc., accelerating acts like it is starving for fuel, then runs super awesome. Pulls every hill like it should, etc.
I don't smash the pedal when it does this as I need the driveline to stay on the truck. Yesterday as I was merging back into traffic, when I looked back forward from the mirror, I think I saw a yellow light in the upper right corner of the dash for a split second. It's directly behind where I run the steering wheel, so I would not see it any other way.

Could this be the final filter plugging with some residual that was stuck somewhere post Davco? Coolant seems clean and proper too. Fuel is not hot, I checked. Or is this a typical DD thing of that vintage?