If that can help you, here’s my most recent upgrade experience : I booked a QR Y ticket last week as I could see availability for J standard award but when I requested an upgrade on the website it said no availability, whereas there was still 2 standard J award seats available. After a few tries I was redirected to the previous form (generating an email to QRPC) for requesting upgrade instead of the online instant process. And less than 24 hours laters, QRPC sent me an email granting my upgrade :-)
So maybe the online process doesn’t work correctly these days and you should try sending an email to QRPC or calling them.