Comment # 8 on bug 1210964 from Doe

I've solved the issue.

What I did:
- changed in the BIOS/UEFI Mode via "Startup ➙ UEFI/Legacy Boot: Both" to "UEFI
Only"
- boot from USB Media
- started the installation process again
- noticed minor changes in installation summary, like
  Update NVRAM: "active"
- changed the follwing item:
  "Systemstart"
  Secure Boot: "active" => "deactivated"
- started the installtion routine
- reboot
=> done; The system re-boots as expected

To sum up:
After the installation I noticed the new OpenSuse boot screen was coming up on
reboot. I guess the installation script wasn't aware of the hybrid UEFI/BIOS
setting of my Lenovo Laptop mentioned above and might prepared the System as
Legacy BIOS Linux client instead of an UEFI-based one. Which means it doesn't
used efibootmgr to write/alter the UEFI boot entry/touch the NVRAM in my case.
I had to "force" the installation process to (re-)write the boot entry in the
NVRAM, by setting the Firmware to "UEFI-only" mode in the first place. 

To be clear:
My conclusion is based on my observation and extremely "not deep-dive
debugging". It could be bloody wrong and I don't want to be rude to the devs or
blame your nice upcoming new OS. I just thought that my case could sand down
the possible rough edges of the release candidate to make a desktop user's
experience as pleasant as possible :) .

Have a nice weekend folks!

Regards,

C.