Might be coincidence, and perhaps your DPF was getting close to getting clogged anyway? Extra soot from a tuning box won't help though.
Either way, it seems daft to me for any vehicle to show a dash light to tell you a regen is happening - it's alarming and distracting; why would anyone care as it is supposed to a normal, regular function. You wouldn't want say, the alternator charging light to come on every time a smart alternator comes on the charge a battery, right?
I want warning lights that are for faults. Or for useful information that I can do something about (like indicators, or headlamps being on).
Is it possible that people are mistaking a DPF light coming on as a result of a real fault, but one which self-clears if a successful regen occurs? I know that the ECU makes several attempts to complete a regen when needed and it remembers that one was in progress if you stop after only doing short trips - maybe the light is about "X" number of uncompleted regens and it means "go for a long drive" ! What does it say in the various manuals about the DPF dash light? Fault or just information?
The plural of anecdotes is not data. Anecdotes however, are better than hearsay.
2014 Nav V6 (quite nice for a pickup truck) & Celtic Rambler (awesome as a mobile luxury flat).