Hey I'm Canadian and applying to Canadian law schools as well! There is a character limit for Osgoode, once you go to submit it on OLSAS you'll see that it's split into two 2,000 character essays.
maybe it is because on OLSAS they break up the 4,000 word essay into two 2,000 word essays? And then leave a 2,500 word optional essay? I don't really get the logic as writing one 4,000 word essay is different than writing two 2,000 word essays