Why are you buying the boards?
There are the usual good suppliers like Gypsum.
There is reputedly a cheap board going around at the moment that practically disintegrates if it gets wet.
ONQ.
[broken link removed]
All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.