The stuffing box packing has been over tightened. Look for cracks in the metal. The bearing was driven too far up a tapered shaft. Any type of flaking or smearing can cause a fracture notch that will lead to cracking. Look for signs of corrosion.
Moisture is in the lubricant.
A water hose being used to wash down the area. Normal aspiration as the pump cooled down, and the moisture ladened atmosphere entered the bearing case. Steam or water from a seal quench gland. This is a common problem with the A.P.I. gland that is commonly used in oil refineries. Check with your bearing supplier for the availability of this information.