A classic conundrum, would you and CRA consider you to be a self-employed contractor or service provider? Or were you acting as a paid employee, told what to do, when to do it?
Did you use your own tools and materials?
Did you receive specific supervision as to work performed? Or were you simply given a goal?
Often, employers use box 48 erroneously based on advice from their accountants.
If you consider yourself an employee in this job, report the amount as Other Income.