Question Is this normal that kinematic rigidbody is interpolating?

I have non-rigidbody character controller and moving platforms which work ideally.
But when I lower timeScale the character begin to move off platform slightly when it moves horizontally and when it moves down character simply lose contact with ground. I even disabled character controller itself, the problem still occured.
The fix was simple, I disabled rigidbody interpolation (it was needed for another feature), but it was kinda unexpected.

What's the point in such behaviour? I'm not even using physics, rigidbody is kinematic, platform movement is caused by transform operations. Why it's hapenning and exactly on lower timeScale?