Misalignment or shaft deflection caused by faulty assembly can cause uneven wear of the bearing. See also wiping due to misalignment.
Addressing the Damage
Fit new or relined bearings or pads, and correct the misalignment.
Alignment and assembly in industrial machines cannot be expected to be perfect and hydrodynamic bearings are relatively tolerant. In principle, however, the tolerance only extends to the thickness of the lubricant film and this can be small especially in low viscosity liquids. The better the quality of the machine build, the better will be the performance of the bearings.
Figure 1: Angular misalignment of shaft or housing, or dirt trapped behind carrier ring, causing damage to pads on one side of the thrust bearing only