Originally Posted by SDQBound

This is wrong.

There are two different cases:

Two medallions on a single PNR: Upgrade will clear at the lowest medallion window, so in this case, they should have cleared at the GM window.

Medallion + non-medallion: Upgrade will clear after the last FO and before any other partner (Skyteam, SPG, AS).

If only 1 seat is available, the PNR is skipped and the next single passenger in the list gets the upgrade.