We have not been able to confirm that the forgivable portion of the CEBA loan is exempt from CPP. Therefore, the forgivable amount is simply added to business income on Line 8270 of the T2125 - Statement of Business Activities, as it is a direct support to businesses requiring assistance.
A sole proprietor will pay additional CPP on the higher net business income. This is an indirect result of the CEBA loan for business purposes, so there's no mechanism in place that says it is CPP-exempt because that's a personal matter.
I seriously hope turbotax has not been recommending this to anyone.
The CRA states it is considered taxable income, it doesn't state pensionable or insurable income anywhere.
I was finally able to get an answer from the CRA after many days of being transferred between departments and senior agents on this and all CEBA/CERS/CEWS/TWS payments go on line 13000 and specify in that line what the other income is.