If you're rebooked by a human at the airport, it's a manual process to add you to the upgrade list, so it's easily overlooked.

If the agent doesn't mention it, be sure to ask if you're on the u/g list before leaving. And of course, validate on the PDA site as well.

If you get rebooked outside the EUA window (or if your connection is outside the final EUA window), it's possible EUA will upgrade you as well if/when it runs.