II. Principles of Law
(d) Teaching on a Casual or Substitute Basis
Claimants who are engaged in casual or substitute teaching during their qualifying period are entitled to receive benefits during the annual non-teaching periods.
The application of paragraph 33(2) (b) involves primarily a question of fact, and that the characterization of a teaching arrangement as "supply teaching" is relevant, but not necessarily determinative. It is theoretically possible that a teacher may have a period of employment as a supply teacher that is sufficiently regular that it cannot be said to be "employment on a casual or substitute basis."
Stephens v. Canada (Minister of Human Resources and Development),  F.C.J. No. 1868 (F.C.A.) A-456-02 Judgments Of The Federal Court Of Appeal
Canada (A.G.) Blanchet, 2007 FCA 377 A-106-06