I also have had changes without notification or notification well after it appears on the reservation. I make it a point to check all my reservations frequently.

As for the change to the CLT departure time, my return flight to CLT in February was pushed back to 5:10 PM. Fortunately I had a long layover in CLT and should be OK. My thought at the time was that AA moved to a later departure time to allow more time for others to make the connection with a same day morning flight through CLT to SXM.