I just had a quite IROP (irregular operation) occurred on me. Let me share the story:
I purchased IAD-DOH-xxx on an AA award ticket in J for travel on 03/11 (with Mrs). We have 001 tickets in hand. We have picked the two middle seats as the IAD-DOH has QR suite. On the day of the departure, QR informed me that we were IDB'ed because we were booked on "mileage ticket"? The only option would be:
1. Fly in Y
2. Travel the next day.

Of course, I did not accept any of the option. After some back and forth, QR rebooked us onto PHL-BOS-DOH-xxx (first segment on AA in Y). Over the phone, QR's agent confirmed our seat assignment and reassured us we would still be in a QR suite. We received the new ticket numbers (157) issued by QR in the email. So far so good. Just I thought everything would be in order, things took an unexpected turn. While we are at PHL getting ready to check in, we received a new ticket (157) for the following routing:
PHL-LHR-xxx (first segment on BA; second segment on a different OW carrier).
We did not receive any phone call from QR regarding the change! This might sound OK but with an over eight hour connection at LHR plus all sorts of COVID-restriction, no way we would accept this new routing. In addition, BOS-DOH still has at least 2J for sale (checked with EF). After some long conversation with QR again, finally we were rebooked back onto PHL-BOS-DOH-xxx but we lost our QR suite. So here is the summary:
1. IF you are on mileage ticket, QR might bump you without any consent.
2. QR might re-route you deliberately.
3. Even though having the ticket number in hand, your ticket is not guaranteed.
4. Seat assignment is not guaranteed.

Thanks for reading my story.