Comment 3 for bug 2049761

Subiquity doesn't export the pools immediately, to allow inteacting with the target system prior to reboot. Once the install is done done - and the reboot button is clicked in the installer, then the very last steps of the install including zpool export happens.

In the case of the listed bug logs, I see unattended-upgrades is still running, so I would expect this result.

I don't believe there is particular action required in the installer, as zpool export already happens during clean exit and reboot of the install. Though perhaps there is room for UX improvements to make this clearer.