ProPay does not process these types of checks - as it falls under the category of Cashier's Checks/Money Orders which they do not process.
These Online Bill Pay checks are checks that the bank cuts on behalf of the Tenant. So the tenant sets up online payments to the Property Manager, they let their bank know to cut this check, the bank withdraws this amount out of the tenant's account, and then the bank sends the check to the Property Manager for the tenant.
However these types of checks cannot be processed by ProPay. So these cannot be scanned in Property Matrix, and instead need to by physically deposited at the bank.