I am currently working on STEM OPT and I have never been filed an H1-B (I missed one chance), I just received the e-mail about sending passport to CIC.
I need to know if I will have any trouble re-entering US on my current F-1 STEM OPT Visa if I activate Canadian PR at their port of entry.
If you have these you’re good to go. I have re-entered twice on STEM OPT. In addition get letter from employer and paystubs etc just in case they ask for it.
Also, CBP preclearance happens in Toronto itself (and a bunch of other airports), so once you clear that, technically you’re inside the US and waiting for a domestic flight.