High shaft speed will cause centrifugal force to drive the rotating face square to the shaft, opening the lapped faces. The lapped faces are not flat. The lapped face was installed backwards. You are running on the non-lapped side. High stuffing box pressure can distort a lapped face.
Thermal distortion can distort a seal face.
The product changed state and is restricting the movement of the seal. The product can crystallize if you change the temperature in the stuffing box. A temperature change or agitation can cause a product to become viscous. Products can solidify with a change in temperature, pressure or agitation. A change in temperature or pressure can cause a product to build a film on the seal sliding surfaces.