The most surprising thing to me in that bulletin is that shoulder harnesses were worn underneath the life jackets by both occupants. I don’t get why they would do that. A daughter has an equine air vest that inflates if she ‘dismounts’ unexpectedly, are these vests similar, or impact/water activated?
It seems very strange that in the event of a controlled ditching, they may have compromised their escape options in having to remove life vests prior to egress from the aircraft.