AC 33/34 have upgrades clear for the whole route at the starting point. So for AC 33 (YYZ YVR SYD), an E can clear both segments and trump an SE waiting in YVR.
Conversely, if you're trying to upgrade just YVR YYZ on AC 34, anyone in SYD going onto YYZ will clear in SYD.
So even if you're SE, don't try to upgrade these flights unless you're requesting in YYZ or SYD!