There are enough AC lurkers on this board that if what is being speculated here was not true, one of them would come out and say it. It's not their fault AC changed the rules, and nor should they take the fall for it, but I do hope that someone high up is getting the message here.
As for where it says J class booking I was unable to find this, but I do recall reading this before. If this airline was honourable they would refund the unused credits for pax who wished to receive a refund due to them buying the pass on a different set of rules. With the cutbacks that have happened this year, I am interested to see what cutbacks they will do for status members packages next year.