Here's a new one, at least for me. I bought a same day return GRR-ORD-DFW-GRR booked in F with DFW as the specific turn point. a few days ago. Since then, there were a few slight schedule changes that did not jeopardize any connection.
Instead of leaving the ticket alone, and simply notify me of the slight time changes, today, the ticket was changed to GRR-ORD-GRR with no notifications (A good reminder to always check reservations periodically.) I chatted online with AA and got everything back to my original routing.
Totally unrelated: Repricing the trip with today's prices. Three days after original purchase, my $488 ticket is now $2700+. Makes ya wonder sometimes,