Perrault said mail-in ballots will not be counted until the day after the election, in order to allow them to be received right up to the last minute before polls close and to give election officials time subsequently to carefully conduct checks to ensure no one who voted by mail also cast a ballot in person.
Straight from the article.
Why do they need to be recieved past poll closing?
Set a shorter deadline for mailing, or put a dropbox outside the polling station.
Problem fucking solved. It's 2021, delaying a vote count is beyond stupid.