A change in temperature or pressure can cause a product to build a film on the seal sliding surfaces. The product vaporized between the faces and blew them open. This can happen with an increase in temperature or a decrease in stuffing box pressure. Solids clogged the springs or some other part of the seal, restricting seal movement. Solids outboard the seal can restrict axial movement as the seal moves to compensate for carbon wear.
Ice can form when some fluids vaporize, or cold weather can freeze moisture in the air.
Crystalls and solids can form outboard because of seal leakage. If you are using a gland quench connection, the quenching fluid must be clean or it will deposit contaminants outboard the seal. If shop water is used in a quench gland to cool a hot fluid be aware that the calcium in the water will deposit outboard of the seal and restrict its movement. Discharge recirculation lines aimed at the moving seal parts can restrict their movement. The seal face hung up in the fretted groove that we find so common in most original equipment seal applications.