So, (using ADI) I created a page (not the main page) that I liked, which had a layout that I wanted to keep consistent and re-use with different content.
I created subsequent pages by duplicating the section that comprised the page I'd designed, and then moving that duplicated section to a new page, and then changing the content. These are all subpages of a top-level page.
All the 'cloned' pages had a URL of the form www/...../blank-n, where n was a system-generated number. But I discovered I could change this on the Settings/SEO Page page, and I did, giving them all 'meaningful' URLs of the form www/..../thisisapropername.
All good. Yesterday I sent a ShoutOut to subscribers with a link to one of those pages, using the new meaningful URL. And the link worked - I tested it.
This morning, I discover that the link in the ShoutOut doesn't work any more, because the page URL has reverted to www/..../blank-n (though n is a different, higher number than it was before).
On the SEO page, though, the URL is still the meaningful one I put in.
So what's happened there? In the time since I gave the pages meaningful URLs, I have made other changes to other parts of the site and re-published - but as the SEO page still has the meaningful URL, I can't see how that can have done it.
And how come the name on the SEO page isn't consistent with the URL on the published site?
(Slight aside - the site's internal links to the page worked yesterday, and still work today, which would imply that the reference to the pages that the site itself uses are nothing to do with the URL given on the SEO Paqe. So what's the internal ID of the page?)
Any help gratefully received. I need to go back to my subscribers and explain why I'm sending them apparently dead links.
PS I've republished, and the URL has reverted to the 'meaningful' one. But who's to say that at some point it won't revert to the 'blank-n' version? So I'm still keen to understand what happened....