Been having a run of problems with grub2 in now two of my Macs, filed a bug
report on that issue where TW wiped grub menu AND now a second machine has had
grub2 function removed, such that Super Grub2 disk is needed to boot the Leap
15.5 option.  In this case there is only one linux system installed that grub
needs to find, but machine boots to "emergency grub mode" . . . showing "grub
2.04" . . . but I thought grub was now supposed to be 2.06???

Filed a post about it on the new forum . . . . 
https://forums.opensuse.org/t/leap-15-5-loses-grub2-function-with-just-itself-to-boot/161710