Before revision: This occurs when contacting bodies vibrate against each other in the presence of very small loads, which pushes lubricant out of the contact surface area, and the bearing assembly cannot move far enough to redistribute the displaced lubricant.
After revision: This occurs when contacting bodies vibrate against each other in the presence of very small loads, which pushes lubricant out of the contact surface area, all while(or rotate far enough) the bearing assembly cannot move far enough to redistribute the displaced lubricant.