AA is notorious for changing or cancelling flights. I have a number of future BA bookings involving AA metal at some point of the trip and I don’t think a single trip has been left unscathed. I have an LHR-BOS-PHX-STS booking next week where both AA sectors have been amended twice. The upside is that often time changes are shown as cancellations and rebooking which allows very flexible possibilities of rescheduling or even cancellation of whole
Itineraries if you wish to do so.