Comment 9 for bug 1799835

I'm far from 100% positive, but it's conceivable this is a duplicate of bug #1789650. The cause there is cold vs. warm booting -- the BootCurrent variable is missing when booting cold, but appears when booting warm. This results in the installer setting the BootOrder variable to the on-disk "ubuntu" entry first during an installation (which begins with a cold boot); but after the post-install warm reboot, the BootCurrent variable reappears.

So, I recommend Dann check to see if BootCurrent is present after cold vs. warm boots of the hardware.