This relates to a Joomla 3.8.7 site where most of the content is available only to logged in users which is done by setting the Access Level on menus/articles to Registered.
There are a few pages that should be publicly accessible, so those are in a category called Public with Public access and the Articles are also set to Public. Those pages need to be accessed by direct URL (ie links in an email that show the article, not accessed via menus).
The problem is that those links are redirected to the login page for anonymous users.
After a bit of experimenting, it seems that this is related to the access setting of the home page menu item: if the home page menu item is set to Registered then all anonymous access is redirected to the login page. This works well for our needs, except for the public pages. If the home page menu item is Public, then the public links work but we lose the redirection for other pages.
a) Is this expected behaviour? ie setting the home page menu item to Registered redirects attempts to access other URL's overriding the Public access configured for them
b) How can I keep the redirect for most access but let the public pages be accessed anonymously?