The elastomer is swelling up under an outside seal face. This problem can also occur if the seal design allows a spring to contact the inside diameter of the hard face. The shaft is hitting the stationary face or the rotating seal face is hitting a stationary object. This is a good reason for converting your pump to an oversized stuffing box. Heat check or cracking of the hard face is caused by a high heat differential across the face.
Most hard coatings have only one-third the expansion rate of the stainless steel base material.
Hard coating coming off the face. The base material not compatible with the sealed product. These coating are very porous so if the product attacks the base material the coating will come off in sheets. The plating process was not applied correctly. High heat can cause a problem with the differential expansion rate between the coating and the base material.