Player stutters on animated gameObject and falls off the other rigidbody object

I have an animated platform and the player stutters as he is moved up and down. Is this because the player’s position is being redrawn each frame?

How can I smooth that out?

Stuttering

On a separate platform with a Rigidbody (marked as Is Kinematic ☑) that moves from a script the player doesn’t move with the platform, just falls off. The player is from the starter assets and has a Character Controller with a basic Rigidbody push script attached.

Should I be adding the platform’s position to the player’s position when they collide?

WalkOffObject