my only conclusion is that Lycoming have let their quality control slip.
Very old news, I think. Most reached that conclusion with the crankshaft failures over 10 years ago starting with SB549, then SB550, SB552........ Nothing has changed.
Similarly, the issue with piston pins has been going on for years and has been reported to Lycoming and regulators in the EU (who have, as usual, done nothing as it is under the FAA's regulatory oversight).
Lycoming could not give a ####. Their customer service is based on the POV that most owners are stuck with Lycoming so they can be treated with contempt.