Foreign objects in the hoistway or on sheaves can "score" the belt as it travels.
If the outer cover begins to peel away (separate) from the inner carcass, complete failure may be imminent. Causes of Abnormal Wear otis gen2 scratch
Otis uses specialized technology to ensure scratches do not lead to catastrophic failure. Elevator Maintenance Pt. 3 - Belting & Bucket Wear Patterns Foreign objects in the hoistway or on sheaves