I remember way back........someone wanted to know why big oil was not sued......think again......this tells a different story.
The oil in question is a group III.......not the true synthetic group IV/V.
The oil filter was also blamed. That's why I use only depth filters with the backing support screen,or the new Bosch Distance depth filter. In either case, a group three oil can sludge and then block the filter putting the blame on the filter when the oil was at fault all along.
This would not have happened with a 100% PAO/GROUP IV/V OIL. No sludge,and no blocked filters....period! Just a super clean engine.
This engine below wasn't so lucky with the group III oil. The opposite of super clean!!
This is the very famous BG product addressing sludge issues and mentions oil quality as an issue.