Dozy, if you were a pilot you would understand why I, and some other pilots, don't want the trim to change by itself when we are trying to fly the airplane by hand. Due to reasons which are not yet clear to us on PPRuNE, the flight control system was not fully functional and it turned things over to the pilots,
but not fully. Because of what may have been an inadvertent nose-up input to the side stick, the trim went full up and the airplane was trimmed into a stall from which the pilots were not able to recover.
When practicing stalls, student pilots are warned NOT to trim into the stall.
That is so when they let go of the stick, the airplane will return to a trimmed speed which is BELOW the stall speed. Further, if you trim into the stall, the trim might not move fast enough to get you out when you need it to. I suspect that these guys were blindsided by the autotrim.
Next question: Were you involved in the design of the FBW system under discussion?