AR-15 Criterion 18" Hybrid/Aero Precision Bolt Defect Fail! Part 01

Not off to a good start! Ejector hole has something stuck in it that would not allow the ejector plunger pin to move flush with the bolt face. At first I thought the spring pocket wasn't drilled enough but closer inspection revealed that something is broken off inside. Part of a drill bit or reamer? Whatever it is it's very hard as a titanium coated drill bit won't touch it!