A friend who was on board says they were told that the engine had lost a blade. Very unspecific, and one wonders how they knew so quickly, but it all sounds consistent.
Most if not all pax seem to have been put into hotels overnight and reaccommodated on a wide variety of flights today. He is on today's NZ1. I've told him that he was obviously not meant to be emigrating to New Zealand and he should regard this as an sign.