In Eoan a workaround for this seems to be to add head -1 to the following line of /etc/grub.d/10_linux_zfs:
initrd_device=$(${grub_probe} --target=device "${boot_dir}")
to
initrd_device=$(${grub_probe} --target=device "${boot_dir}" | head -1)
This limits the initrd devices to 1, this is only a workaround for this bug
In Eoan a workaround for this seems to be to add head -1 to the following line of /etc/grub. d/10_linux_ zfs:
initrd_ device= $(${grub_ probe} --target=device "${boot_dir}")
to
initrd_ device= $(${grub_ probe} --target=device "${boot_dir}" | head -1)
This limits the initrd devices to 1, this is only a workaround for this bug