Have you verified that it is a multi entry passport. It can be valid for 2 years but may be a single entry Temporary passport.
I've never heard of a single entry temporary passport. Not saying it's impossible, but never heard of one. And pretty sure that if they did issue one, it would not be valid for two years - only for a shorter period of time (i.e. weeks) to travel to Canada.
There are emergency travel documents that can be issued, as well as a few other rarer, for limited-use purposes as well.
But a two-year validity passport, temp or not? Multi-entry.
And remember: Canada doesn't restrict
exit of its citizens at all, and can't constitutionally limit entry. (Although technically can not issue a passport)