I've brought this up in a few threads, but the narrative about his defense has largely been untrue so far this year. His play on that side of the court extends back to last playoffs with the Blazers too. He might be figuring out a few tricks to be average and sometimes disruptive on that side of the court.
I think there is a newish model of big man pick-and-roll defense. I've seen Jokic do some of this as well. The old model is simple, ice the ball-handler (not new) while your teammate gets over the screen and forces a non-three. Then, invite the ball-handler into no-man's land, where few want to take a mid-range shot. When the ball-handler gets into no-man's land, normally they are a bit uncomfortable. Can they confidently pull-up? How about do a floater? What about attack a clogged paint?
What is new is that players like Kanter and Jokic have been using their quick hands and great hand-eye coordination to go for strips or deflections while the ball-handler is dribbling or as they gather. They do this at times instead of challenging the shot up high. Normally, this has been considered a defensive play made by little guys, and the big guys were supposed to defend the rim.
It's not like you can do that every single play. But if he can get deflections and strips on timely plays while he is in the game, it helps increase leads until the starters get back. In other words, Kanter's defense is helping the team win games.