I just made a minor change to my QR reservation (moving to a outbound flight few hours later). Noticed after some time that the 2nd connecting segment didn't get confirmed and was showing twice. Was emailed a confirmation of the miniscule fare refund and "confirmed". Etkt appeared to be reissued; different number.

Called QR reservations and they resolved the issue. She just put me on the QR marketed flight instead of the AA codeshare. Manage my booking didn't show unconfirmed anymore and seat selections could again be made.

Not unusual that the system messes something up during a rebooking. Highly doubt a QR plat is picked to be bumped.