In British Columbia you cannot be on both Persons with Disability (PWD) and CPP Disability at the same time. You are required to apply for CPP-D once you are approved for PWD. 

What isn’t made clear is that policy is retroactive. If you are approved for CPP-D, you are required to pay back any welfare/disability assistance you received.

For me, this meant the BC government received a huge amount of money since my case went for 4 years.

This policy making it so you cannot collect both retroactive is wrong and is stealing money from people on disability. If the government truly wants to help people on disability, then this policy needs to be reviewed.