Looking for "Teething Problems" in the curriculae....
The TRENT's problem was a lack of (proper) material in the IPT shaft, it is memorialized in the AD. That is not a teething issue, that is a spec/engineering mistake/blunder.
The "misaligned Stub Pipe" likewise is a blunder in machining and QA. I will continue to consider these facts and be sceptical of marketing/promotion issues that fly in the face of quality, and attempts to downplay the seriousness of these issues.