Comment # 14 on bug 1174412 from Fabian Vogt

(In reply to Andr�s Barrantes Silman from comment #13)
> After running the other commands, the new boot entry "efibootmgr-manual"
> does not work either. It also points to the hard disk.

Ok, so it's efibootmgr or efivar doing something weird, reassigning.
For completeness, what does blkid say?
blkid /dev/sda /dev/sda1 /dev/nvme0n1 /dev/nvme0n1p1
blkid -p /dev/sda /dev/sda1 /dev/nvme0n1 /dev/nvme0n1p1

> =drive shows:
> 
> (hostdisk//dev/nvme0n1,gpt1)
> 
> =disk shows:
> 
> /dev/nvme0n1

That confirms grub2-probe is working correctly.

> Considering I had to do so many workarounds to get the Leap installer
> going... neither Balenaetcher, dd, or Rufus worked on Windows. Imagewriter
> on Leap did work and the installer now loads.
>
> How did I start the installer? Somehow, the live iso did boot, so I added
> the DVD iso as a repository and the installer worked, business as usual from
> there.
> 
> Probably that confused something in the install process.

Possibly, but that would still be a bug and it's also reproduable manually
apparently - AFAICT the system is configured correctly and there's nothing
weird going on like duplicate UUIDs.

> Anyways, now that I can load the installer, I might reinstall, just for the
> sake of it. I still want to see what went wrong in case there is actually a
> bug lying behind or it happens again.

FWICT, it does actually look like a bug.