Canada is a program member and a prospective customer.
If Canada acquires F-18E/F/Gs as an "interim" measure pending final testing of the F-35 and software, with the stated intent of an eventual purchase, it remains a program member and prospective customer.
It would be interesting to see the legal consequences and court cases if LM proposed withdrawing contracts based on such a buy - caused by the LM slippages in F-35 delivery.