I'm seeing results sporadically appear and disappear from second to second, as in running the same search a few seconds later will cause a result to disappear, and then running it again a few seconds later makes it appear again. Clicking the AC.com link does not show the seat on AC.com, and for what it's worth I can't find the seat on UA's website either, so it seems like it may be phantom space? Is this a known issue with the Air Canada backend or would you like more details to investigate?