Your ticket almost certainly fell out of the queue. Perhaps the original agent didn't set it up correctly for ticketing, or there was a schedule change (or slight schedule mismatch between what AA was showing when you held the ticket and the actual schedule, even a minute off). Likely the reservation needs to get cleaned up before ticketing - and the first agent you spoke to didn't see the issue.
If you hang up, call back enough you should be able to get the agent to get the appropriate folks to ticket while you hold. But at a minimum keep calling until you find an agent that sees something wrong.
Don't accept that ticketing takes time, and that they process in travel date order. AA doesn't do instant ticketing of partner awards, sure, but it shouldn't take much more than a day for the furthest-out dates. If it takes a couple of days during the busiest ticketing times (e.g. reissues during major weather events) I call back.