Not sure if it's RFE. Do we get an email if it's RFE?
the message in the Inbox says
The U.S. Consulate in Montreal requires that non-Canadian citizens submit proof of eligibility to have their visa interview in Canada. Please submit one of the following: Canadian Legal Permanent Resident cards, landing papers, student visas, or work visas.
I only received an update email, then Civil Documents and AOS are accepted also.