Phil gollin,
[I think calling the AAIB suggestion a "theory" is a little bit too optimistic - they do not think there was enough water to form sufficient ice, and can't model a reasonable event to cause damage.
I think it is merely something they are investigating.
....and something that 2 of the 3 AAIB Safety Recommendations addressed. Concerning the semantics, "theory" seems appropriate as defined by the OED. On your comment about there being insufficient water to form ice, isn't that what I said?
Rgds