Hi there.
I want to share the information that I received calling to CBSA, and to a senior officer. U.S nationals are able to cross certain ground borders, which had the newest updates. They do have really strange schedules, therefore call before you go ahead to cross via ground border, they are no operating 7/24. I used to live in Montreal with a work visa before the pandemic started. As a new doctoral student, my Graduate Lab is open and therefore I need to be there for my doctoral studies (I got the support letters). Therefore my case is no-discretionary and have some chances to be granted. Unfortunately, I have only the AIP letter so far and I don't think the SP will be issued any time soon.
Also, I had received information from a lawyer that several U.S students had been granted their SP and WP at POE.
I will try next month and will be happy to share my experience.
All the best