What can be causing this?

[Thump_rrr]

This is the bolt from my Mark II TRR-SR.
I bought it used about 8 years ago.
I probably put about 1,000 rounds a year through it.
Today I decided to clean and inspect the rifle and I found this.

Anyone know what could be causing this.
Should I use a stone to remove the burr?
Do I need to do anything going forward?
https://i.postimg.cc/gkV9kR3z/1-BDE5-C45-FCB7-4-A93-BF65-6-FB6-CAE8-DBAF.jpg (https://postimg.cc/dLVN5hWp)
https://i.postimg.cc/X7SSbxG1/4-C28-EB65-D3-E4-48-B9-96-AF-F04-AD5392216.jpg (https://postimg.cc/Yj3yN6xQ)

[sharpshooter]

That is common. It is where the front of the sear hits the bolt and acts as a bolt stop. The burr won't hurt anything mechanically, but if it's sharp and dangerous, file it off.