"Sliding"
I had a tought. What if the gravity is so weak that the simple rotation of the body on itself could give escape velocity to an object on it... for Phobos, if its rotational surface speed at any point gets over 11.4 m/s, the object would get escape velocity. It seems that Phobos is rotating on itself slower than that, unless it would break apart due to centripetal force.
It's clearly not the issue you're having because that would not be showing red debug text...