fKn, this is because of your line that says:
# kopt=root=UUID=5e0b2840-d37e-4e69-842c-3be3bd16819c ro
If you change this line back to:
# kopt=root=/dev/sda10
and run "sudo update-grub", it is set back to the same UUID?
Olivier, do you have other hard drives on your computer?
fKn, this is because of your line that says: UUID=5e0b2840- d37e-4e69- 842c-3be3bd1681 9c ro /dev/sda10
# kopt=root=
If you change this line back to:
# kopt=root=
and run "sudo update-grub", it is set back to the same UUID?
Olivier, do you have other hard drives on your computer?