Issue was introduced with
https://build.opensuse.org/request/show/455437

And detected by openQA in several tests:
GNOME Live : https://openqa.opensuse.org/tests/352734
KDE Live   : https://openqa.opensuse.org/tests/352732
Rescue CD  : https://openqa.opensuse.org/tests/352726

The issue boils down to:
/etc/resolv.conf is now a symlink to /usr/lib/systemd/resolv.conf

This happens only on the live images (so far) because they do not have a
'pre-shipped' resolv.conf - and systemd contains instructions in
   /usr/lib/tmpfiles.d/etc.conf

to produce that symlink

This part of tmpfiles.d should also be moved to the systemd-resolv package, so
that the absence of this package means no ill side-effects

For the time being, I am reverting systemd to the previous revision in
openSUSE:Factory

*no Tumbleweed snapshot had been produced with this systemd package - openQA
blocked it)