I used SDFC for the first time in a long time (possibly ever) for my flight from SAN-DFW Today. I had several options to choose from, and when I chose my flight and went through the process, the system would "churn" and return an vague error message. This was on the app, and I had a similar experience on AA.com so I called the desk. The agent also had a difficult time making the change on her end and finally concluded that the trouble was due to the fact that the ticket was booked through a third party. She eventually was able to push the change through, but she said she had to do it outside the normal procedures/channels.
My ticket was booked through our corporate travel agency using Concur.
Has anyone else had trouble using SDFC on a ticket booked through Concur?
Another odd piece of this was that when it came to the seat assignment, she wasn't able to book me into my preferred exit row seat because it was making her charge me, and she advised that I change the seat myself. Once we got off the phone, I pulled the new flight up in the app and was able to select my exit row seat as normal, with no charge.
Another data point to add is that i did not loose my Pre Check status during this process (as has been reported by others).