John Deere 14t Billhook Damage

[DB1200]

Hello, last hay season my baler started messing up knots on the right side. Seem to be the same thing is was doing on the left the year before. I replaced a worn bill hook on the left and it fixed it. So I decided before this year hay season I would replace it on the right side. When I pulled the old one out I had found the roller was beat up pretty bad. What causes this type of damage to a bill hook? Thank you.