I'm seeing similar glitches for an upcoming trip upgraded with miles.

Some segments show different seats depending on where I look...the overview screen online, the seat selection screen, and various screens within the mobile app. Some screens show the original, purchased seat. Others show the upgraded seat.

Both seats for the glitch flights are grayed out in all views, which suggests that the system may have placed me in both seats. Even when the seat map shows me in economy, the first class seat remains blocked out and the upgraded class of service is listed.

A phone agent assured that he saw the upgraded seats I had selected, regardless of what the website showed.