google+ share problem with posts being shared publicly

A quick update on the cross-platform post sharing experiment mentioned here.

Twitter works a treat, but for some confounding reason, google+ refuses to sharr the post publicly.

The archaic (and immensely unhelpful) logic requires the post to be deleted and reposted. An utter unsurprise then, to me, to find the root cause seems to be my poor decision making in deciding to select share with groups when setting up the share.