grub-mkconfig 2.06_rc1 fails with GRUB_DISABLE_LINUX_UUID=true for a BTRFS fs (raid1 for data) spawned over 2 partitions

[Toralf Förster]

It generates:

                load_video
                if [ "x$grub_platform" = xefi ]; then
                        set gfxpayload=keep
                fi
                insmod gzio
                insmod part_gpt
                insmod fat
                search --no-floppy --fs-uuid --set=root 76E9-FC72
                echo    'Loading Linux 5.12.2 ...'
                linux   /vmlinuz-5.12.2 root=/dev/nvme0n1p3
        /dev/nvme1n1p3 ro net.ifnames=0
                echo    'Loading initial ramdisk ...'
                initrd  /initramfs-5.12.2.img
        }

Please not the line break and the 2nd device name.
.

With uuid it works fine:

        echo    'Loading Linux 5.12.3 ...'
        linux   /vmlinuz-5.12.3
root=UUID=59ad41c2-dedb-4097-99b2-6f404280ede4 ro net.ifnames=0
        echo    'Loading initial ramdisk ...'
        initrd  /initramfs-5.12.3.img

--
Toralf