My clutch has started to become chattery on my foot when release around 1k rpm. Had the clutch replaced last year because of improper installation. When I give gas and release around 1.5-2k it doesn't chatter or shake the car.
Sounds like time to make use of warranty. That being said, my car clutch does that same, what did improve it, was replacing the lower, rear torque mount with the 2014 ford focus electric mount. No modifications are required, just remove and replace. Mazda should have assembled the cars this way. It removes the rubber band feeling