Problem is most of those points are coming against weak teams (Vancouver, Seattle, etc.). He is not doing that well against the good teams besides STL, and neither is Colorado in general.
13 points in his last 5 games; all against teams that are going to be well out of a playoff race this year. Still leaves him with 10 points in 10 games, but another 6 of those points are from more games against teams well outside of a playoff race.
Moral of the story is, Colorado has had a fairly light schedule thus far and has been far from dominant, and Kadri is dominating against weak teams but is meh (or worse) against good teams while getting a ton of minutes. He is still a good player, but for the most part, I think he has been a fair bit worse in Colorado than he was in Toronto.