Easiest way is the low-tech way - ring QF and just ask them to reconfirm the reservation.

I have experienced similar things in the past week, all with the same AA agent, who is actually very nice, and I don't want to mention his/her name.

The first one was to date change a DONE4. It was a CX flight. I was told I would have to go to an agent to have the ticket reissued. I was in Sydney at the time, where there is no AA office, and didn't particularly want to go to a random travel agent and see what they could do, so I called CX office to see if they could see the booking, which they could. There was no problem at checkin.

Then a couple of days ago, I made changes to a separate DONE4, this one did not involve any CX flights, only AA and QF. They were only date and time changes, but again I have been told (coincidently, by the same ticket agent) that I will have to go an AA ticket counter to have the ticket reissued. I haven't done this, but flights are now tomorrow morning from LAX, so I should probably get to the airport a little early incase I have any problem. Will report back with the outcome....

This is NOT POSSIBLE as QF did not issue the ticket. If you called them they will say - refer to your Travel agent. In this case It is AA!!

The reason is that they can't see the ticket and don't know whether they will break any rules by changing. Also they prob couldn't be bothered checking the fare rules for u!

Did you try calling back at a different time, such as M-F 9-5 DFW time?

Is this a paper or E ticket?

It was 9-5 DFW time. And was one of the experienced agents.
E-ticket.

To follow up, I had no problems when checking in at Sydney.
I have been travelling on this ticket for the last month or so, and have made many date/time changes, mainly thru the DFW office. Have had no problems since, but they have always had to reissue the ticket- no fee, of course. I would always get an email a couple of hours later with the new ticket details.

The only problem I had was yesterday, when I was at LHR and EF advised me that my preferred flights had become available for MIA-JFK for the next day. It was very early in London, so both the DFW, Dublin, CPT & Australian offices were closed, leaving only Tokyo that I could think of it. They were very helpful in changing the flights, but when I arrived 10 hrs later in MIA, and hadn't received an email with the new tickets, I thought I would check at the ticketing desk. And, while Tokyo had changed the reservation, they hadn't known to reissue the ticket, so it was good that I had checked at AA ticketing...

Moral is to use Dallas office or another of the bigger offices, and to make sure that you get the email...