During "online update" with yast2, zypper is updated first. The package manager
tries to restart but fails with:
Caller: /usr/lib64/ruby/vendor_ruby/2.5.0/yast/yast.rb:186:in `import_pure'

Testing zypper separately, reveals:
> zypper refresh
zypper: symbol lookup error: /usr/lib64/libzypp.so.1722: undefined symbol:
_ZN4YAML6detail9node_data12empty_scalarB5cxx11E

libzypp is: 

937453 4 lrwxrwxrwx 1 root root 19 Jul 12 05:44 /usr/lib64/libzypp.so.1722 ->
libzypp.so.1722.8.2

On another machine, zypper runs well with libzypp.so.1722.8.0. I am avoiding
the update for sure.

Hence, almost locked in or out ....
Thanks for looking into this. Cheers, Martin Schmidt