The experience of one or two of the earliest applicants makes it clear that CIC will return applications if they don't have a copy of your ECA - even if you wrote the reference number in your EE application, and even if they don't ask for it!
I suggest uploading it with your other educational documents.
IMO, this is a real mistake on the part of CIC, and it was reasonable to expect that, as with the IELTS certificate, CIC would use the provided reference number to check the veracity of the report, or would ask you to upload it if they wanted to see it. That has not been some people's experience, so everyone should be VERY CAREFUL to include a copy of their ECA when they upload their PR application.
I suggest uploading it with your other educational documents.
IMO, this is a real mistake on the part of CIC, and it was reasonable to expect that, as with the IELTS certificate, CIC would use the provided reference number to check the veracity of the report, or would ask you to upload it if they wanted to see it. That has not been some people's experience, so everyone should be VERY CAREFUL to include a copy of their ECA when they upload their PR application.