Well, sounds to me like you have a bug that needs the attention of an OE
specialist. Have you tried toggling the setting? Change it to something else
using the Settings dropdown at the top of that column? Before trying that,
though, read the following. Better to be safe than sorry if the experiment has
unexpected results.

If you want to archive messages from newsgroups, you should copy them to a Local
Folder, because one of these days those messages are going to be removed from
the server, and you may very well lose them anyway. In short, messages left in
an NG folder aren't safe. They are relatively much more safe if you copy them to
a local folder (and more safe if you save them as files or print them out). Just
right-click on Local Folders, click on New Folder, give it an appropriate
(short) name, then just drag the messages over from the NG folder.

Easiest done by
1.  Select (highlight) "Local Folder" then right click.
2.  Select New Folder
3.  Give it a name e.g. System Info.
4.  When you spot a NG post you want to keep, right
click on it, then "Copy to Folder . . . " and select System Info.
5.  You can keep these posts as long as you like.  Your PC
will still display them when they have been deleted from
the NG server.