Comment # 11 on bug 1008737 from Michael Chang

(In reply to Josef Reidinger from comment #10)
> from logs it looks like no value is set. 
> Michael - how grub behaves if default is set to "saved" and no value is
> saved?

It will fallback to the first entry. If not then it's a bug.

@Freek,

Could you please test reverting the save_entry settings that YaST did for you
and retest with $default with unset value, to know it really cause of problem ?

 # grub2-editenv /boot/grub2/grubenv unset saved_entry
 # reboot

Thank you.