I'd check it real close for a corresponding burr on the piece of metal that caused the burr on the trigger assembly. Could be something got caught between them and caused the damage. Good that it's at least working again.
the part it contacts is the bolt body itself. I checked that quite thoroughly for burs as son as I got it loose enough to take out. I'm not sure if it was a small pebble or what but whatever caused it is gone now.