Add cover and description properties to a note, then publish it.
Did you follow the troubleshooting guide?
Can’t really do sandbox testing for Publish (can I?)
<meta> fields set properly
Both description and og:description are just the title of the note. No preview cover is set at all.
Not sure if this has anything to do with the move from directly editing of frontmatter to properties, but more probably it’s a server-side something, as the notes, where all the metadata was set properly previously, also stopped showing the correct metadata, despite no updates from me for these notes. E.g.: About Me - dsent.me - Obsidian Publish