Looking at the pic of the tube, it must be in the region of 20mm diameter, if the 5mm is a scale reference.
Are there any other views of it?
I have a background in precision engineering inspection (not aeronautical) and from the one pic I could not tell where the manufacturing error is - too many odd angles and much material is missing. Be interesting to spend some time checking it over.
I'd also like to know how it was made. A non-concentric counter bore is actually quite hard to achieve in a turned component (assuming it's turned, of course). If it's been CNC'd there's a whole batch of tubes with the same fault... A thorough procedures audit is probably being lined up somewhere.
How is it decided that this part was damaged in service rather than during the incident?