T-221 people

[vectorit]

While separating my tcase from the adapter, this was found and the guy helping me says that that groove isn't supposed to be there.
The consensus has been that the bearing cage shrapnel has carved this groove over a long period of time.
There is a lot of meat behind this groove, so I am not worried that it will be a problem.

My question is this: Those of you who are familiar with the T-221 adapter, is there any kind of groove there from the factory to begin with?

Just wondering if that groove is 100 percent caused by metal grinding at it, or was there a more shallow groove there originally and the metal chunks just made it bigger.