Squib
I am not quite sure why you are re quoting older posts here but the use of a bypass valve manually (S-92) or automatically (AS332 or EC225) to stop oil going to the cooler is logical as the cooler is a likely place for a leak. EC had automatic oil cooler bypass valves 30 years ago. Why Sikorsky could only manage a manual valve has always been a question in my mind.
Anyway, the leak in both cases was from the filter bowl with terrible consequences.
In the case of the S-92 Sikorsky has now re designed the whole filter bowl assembly (a 2 phase re design but phase 1 is in place now) so I would imagine that the company has gone a very long way to making sure that the oil remains in the MGB casing where it should be.
In my opinion, all transport helicopters operating over hostile environments should be mandated to have a supplementary lubrication system so that the realistically impossible goal of run dry should not be necessary. A few liters of mostly redundant oil in a tank would be a worthwhile thing to have.