I used zypper dup from Leap:15.0 to update to the same Tumbleweed snapshot on
an HP pavilion laptop born mid 2018. I resized the windows partition and
installed Leap:15.0 on it. I set it up to boot from grub, which I use to boot
windows 10 (mainly for netflix download and play later) the boot system has
survived monthly windows updates without a problem.
The first reboot after zypper dup to Tumbleweed failed with "failed to find
grub_efi_allocate_fixed" I fixed this by booting installed system from an
installation usb stick and running yast2 bootloader but firstly after running
yast bootloader and changing the boot menu timeout fro 9 to 8 it went wrong
again, fixed it with boot installed system then running yast bootloader again.
After a Windows 10 driver update - same problem again.