Hey brother, this is very sad news. I know someone who was in exact similar situation but when he re-applied, he got a support letter from the supervisor/school saying that his visa should be issued. I know its ridiculous to provided a support letter when you already have a offer and funding letter but that's what worked for him. Past few months have showed that IRCC is one of the most incompetent authority. I have so many friends doing their PhD in US and they even reached their Universities whereas we are still waiting for PPRs.