AnimatePhysics soesn't work for Animator component (5.2.3p3)

Hi,
I'm not sure if the thread should go in here, it's 50-50 physics-animation, not sure where is the problem.

Bug:
1) Create Box
2) Create Animation for it in Animation Window
3) Add Collider / RigidBody (Kinematic) components
4) Switch Update mode to animate physics in Animator Component
5) place another physical and this time not animated box above the animated platform (enable gravity)

Behaviour:
when platform moves in xz plane, box above slides on it despite all possible settings of physical material settings
when platform moves in y axis (only) - box rises and falls as expected, friction is broken though (same as xz plane)

I don't know if I did something wrong but:
when i modify example above to
6) remove Animator Component
7) add Animation (Legacy) component, mode to animate physics
8) change "Animation clip" that animates rigidbody in debug settings to "Legacy" (to make it work with animation component)

It works as expected

Thanks
Petr

PS. - no joints, changing fixed positions or rotations flags of rigidbody makes no change (as expected - body is kinematic)