Great post, I have a 14 that has 12,800 on it, bought it in Feb with 4300 miles. It has the identical problem. Mine started just after an 1800 mile tow trip and the mileage was 10K. It used to regen once a tank (also in the winter), since the first of June and 10k on the odometer it's been regening every 75-125 miles, just like someone threw a switch.
The only difference is I've found mine go into an active regen twice when the soot% was below 25%. Once at 11% and the other at 23% both times were towing and both times it stayed in active regen for 8-10 miles after the soot was already @ 0%.
The selling dealer gave me the same answers, nothing wrong with it. A second dealer has been much more helpful and found an updated flash and seems genuinely concerned about helping me get it fixed. I know who will get my new vehicle business in the future.
Anyway, if anyone has any insight into this it would be greatly appreciated by me and I'm sure the OP.