A FlyerTalk Posting Legend
Join Date: Sep 2012
Location: SFO
Programs: AC SE MM, BA Gold, SQ Silver, Bonvoy Tit LTG, Hyatt Glob, HH Diamond
Posts: 44,387
Speaking from experience, there is pretty much no way they're going to rebook you on a FP to include another airline if AC offers a non-stop.
Why were you not able to request an upgrade again? Or did J become full?
Another option might have been to call the concierge, as they're MUCH more likely to let you keep your upgrade in IRROPS, if there's positive J space.