I have three segments and wanted to change one of my three flights to have an earlier flight to have longer connection in one airport. The app offered it as a SDC option, chose the flights. And it ended up changing a different flight that I hadn't selected and not the one I wanted. Was able to SDC right back to my original flight but not sure how to get the actual flight I wanted, contacting AA they said there was no space available, which matches what the website shows too. Just not sure why the app is messing up the flights.