To reproduce:
1. Open attached project
2. Open TestScene and enter play mode
3. A kinematic 3d rigidbody has no problems following the rotation of it's parent, but the kinematic rigidbody2d gets stuck
4. Making a bigger gap between the parent and child cube allows the rotation to happen, but the child object is not rotated correctly (see screenshot)

Furthermore, setting the child to be non-kinematic produces even weirder results - it gets hit by the rotating parent, flies off and sort of tries to follow the rotation (in an orbiting motion), but it's collider flies away like there was nothing effecting it