If one runs the command until last week or so it exited (with failure) but pointed out that it is deprecated and provided a link to https://docs.gitlab.com/runner/register/index.html

    gitlab-runner register

documentation pages that once again stated the obvious. No difference at all. Then you rerun the command - same bounce out. No clue. The docs linked at the URL still say to use the --registration-token.

finally (after digging into stackexchange and gitlab issue) one needs to run the command without

    --non-interactive

No where in the documentation it (until last week) that this should be removed for registering a runner as of today (last few months).