I may have had the same agent when recently booking an AA PHL-MCO on Avios. Contrary to what the agent believed, there was Milesaver availability in F on the flight I wanted. My AAdvantage account took me through to the payment page but I wanted it on Avios. I was told quite succintly that there was no availability and that‘s that. Not being one to accept no for an answer I insisted he use the OneWorld desk, call AA or pass me to a supervisor. After being on hold for 10 minutes, he came back with a „looks like something just became available“ comment. However, the offline fee was waived without that being an issue and the agent obviously lived to irk some other poor customer.

PS. I am still getting issues seeing US availability, both for AA domestics and for BA US departures.