I hadn't noticed that a new post is required to clear a previous post on the 'Forum View'!
Not entirely the same issue, although perhaps connected, there seems to be a time delay (of about ten minutes?) over the site, apart from the 'Activity Feed'.
The 'Activity Feed' shows a line for each edit of a post (in full) but all amended to show the last edit.
This time delay also happens in the 'Whos' Online'/'View All' section.
If we sign out, close the browser & remove all cookies (with a programme that does this effectively), we are still shown as signed in for quite a while.
If viewing as a non-member (or signed out), the time delay also applies.
Is this a design feature or an error?
Will check it out further.