Originally Posted by
compressor stall
likely made from different thicknesses. Might be an issue of brittleness at the thickness of a Airbus skin.
Although I suspect - as Flight Detent posted above - the reason is that at in the A320F at the limit of -70*C ventilation valves can start to play up. Seen it.
My hunch is the other way around, the valves are tuned down to the limit and a little less, once exceed they get confused. A symptom as opposed to reason. BTW, have you not actually also first
heard it?