Did you submit these proofs with the application when applying. Not the job offer ofcourse as you might not have had it that time but other things like letters from friends and family knowing your plans, letters from family who're there already, offering you a place to stay for the initial settling in period, rental searches, a letter from you to the visa officer explaining "your plan" of how you intend to re-establish life in Canada, living off savings till you get a job, your employment potential, your research screenshots of newcomer agencies, screenshots of travel insurance to cover for the initial months until your provincial health cover kicks in and so on..
If you did all that in the start its not necessary that they'll ask you for proof of intent to return to canada at this stage. So did you?