News Web Part - sort order suddenly changed to prefer top level site

[CjSyP]

We are using the news web part to display news posts from a top level site (using SharePoint online) and several selected subsites.

Yesterday, it changed without being edited and seems to be favouring all posts from the top-level site over any other site, so it shows only posts from the top-level site now when it's one of the selected sites, even though they were first published (and were last amended) much less recently than other sites' posts.

This seems to happen whatever the layout, number of posts to show, etc are set to. All of the News Order postions are set to automatic; my understanding was that if that was the case then the posts would be shown in descending order of when they were first published, which is what we want. However, as I said, this just suddenly changed yesterday. Has anyone else seen this? Or does anyone know why it might have happened?

(Sorry, this is my first post on here - hope it's appropriate.)

[#2]

This rectified itself a few days after we suffered the issue. I have since found several posts on this site and others where people have suffered similarly. We did nothing that changed the way it, either initially or to rectify the problem, so we can only assume that there's something in the implementation of changes under the hood that causes the issue for us and others.