I thought the universal child benefit was non taxable?

[TurboTaxKim]

The Universal Child Care benefit - UCCB was a taxable benefit until it was stopped in June 2016 and was reported on an RC62 slip. 

The Canada Child Benefit - CCB (which is what is received monthly since July 2016) is not taxable, and does not need to be reported on your 2017 tax return.

Although the majority of people will not receive an RC62 for the 2017 tax year, the slip will still be issued to anyone who received "back pay" for UCCB benefits prior to July 2016, or if you had to make a repayment.