Cube with RigidBody sliding on it's own

Unity Engine
1

I have a 3d Cube object that falls on another 3d object that i’m using as a floor. Both have RigidBody components. When the cube touches the floor, it starts sliding on the x axis at a speed of -0.02. The floor is completely flat and not tilted, and there’s no script making it move. Even if i tilt the floor on the opposite direction it still keeps sliding uphill.
After looking online i’ve seen a few people with the same situation, but couldnt find a solution. If anyone has any clues on what causes this, please help.

Gallery with images to illustrate:

[Album] sliding problem
2

Make the rigidbodies on your level geometry kinematic: Unity - Manual: Rigidbody component reference

Alternatively if the object never intends to move, remove the rigidbody entirely.