There is no way to tell from that document whether any onward carrier has had the ticket pushed to that carrier. The receipt shows a reservation on AY 804, but a reservation is not a ticket and it is the ticket that gets AY paid.
The only rational way to confirm this is to look at your booking on the other carrier's website, to call, or to hold a paper ticket which would include a flight coupon for the AY flight. The first two may be a bit tough depending on your timing. The third is annoying for the agent and for you as well as whoever is standing behind you. But, despite the fact that this is 2017, these systems don't all talk to each other correctly, agents are unevenly trained and as fair warning, the average gate agent could screw this up in a second.
Bottom line is that UA documents won't help much with an AY claim that it had no record of your ticket and never received anything to indicate a ticket.